Facebook has finally forgotten about that drunken night in college when you vomited on that one friend who never talked to you again. Any deleted photo from that episode, or any photo deleted by users for whatever reason, has finally been removed from the social network's servers, it appears.

(Now if only your friend could permanently forget about the incidence too.)

Since 2009, Ars Technica's Jacqui Cheng has doggedly tracked how long it takes big photo-sharing sites to permanently delete photos after a user hits "Delete." Her method was simple: save a photo's URL, delete the photo and wait to see how long it takes for the link to die. For Twitter and Flickr, it took seconds. For MySpace (remember that?), it took months. But for Facebook, Cheng found it could take years.

In some cases, photos deleted in 2009 were still on Facebook servers in 2012. In February, Facebook explained to Cheng "[w]e have been working hard to move our photo storage to newer systems which do ensure photos are fully deleted." Now, Cheng is happy to report that she has "tested this with two photos while saving their direct URLs, and both photos became inaccessible within two days of deletion." Her readers got similar results.

First, let us say, Good job, Facebook. Like how we train a dog, we ought to reward good behavior as well as punish bad. The media, rolling up its newspaper, has knocked Facebook on the nose for many no-nos: swapping users' listed email addresses for Facebook addresses, accidentally showing people's private chats to the public, to name a few snafus. We're glad to finally give Facebook a treat.

But why did this take so long to implement?

"The systems we used for photo storage a few years ago did not always delete images from content delivery networks in a reasonable period of time even though they were immediately removed from the site," Facebook told Ars Technica on Thursday. During its period of massive growth, Facebook apparently found it difficult to expand its servers and delete photos in a timely fashion. But now that new photo storage, installed in February, apparently deletes photos within 30 days, according to Facebook.

Perhaps what this tells us several months later is that Facebook wanted to get serious about privacy -- including making sure that unwanted photos weren't being stored after users tried to delete them -- as it hurtled toward its initial public offering in May. As a publicly traded company, it's reasonable to expect Facebook to be more sensitive to privacy concerns.

And maybe, as Facebook's growth begins to level off, as some believe it to be, it can shift its priorities from making sure servers can support lots of new users to making sure servers don't do things that irk existing users. Having photos you don't ever want anyone to see exist forever on the Internet is awfully annoying, isn't it? Mark Zuckerberg should know. Last year his private Facebook photos were leaked to the entire Internet. Because of a glitch on a server.

Related on HuffPost:

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  • Your Birth Date And Place

    While it might be nice to hear from Facebook well-wishers on your birthday, you should think twice before posting your full birthday. Beth Givens, executive director of the <a href="http://www.privacyrights.org/" target="_hplink">Privacy Rights Clearinghouse</a> <a href="http://finance.yahoo.com/family-home/article/110674/6-things-you-should-never-reveal-on-facebook">advises</a> that revealing your exact birthday and your place of birth is like handing over your financial security to thieves. Furthermore, Carnegie Mellon researchers recently <a href="http://arstechnica.com/tech-policy/news/2009/07/social-insecurity-numbers-open-to-hacking.ars" target="_hplink">discovered</a> that they could reconstruct social security numbers using an individual's birthday and place of birth. Rather than remove your birthday entirely, you could enter a date that's just a few days off from your real birthday.

  • Your Mother's Maiden Name

    "Your mother’s maiden name is an especially valuable bit of information, not least since it’s often the answer to security questions on many sites," writes the <em><a href="http://bucks.blogs.nytimes.com/2010/10/12/what-not-to-tell-facebook-friends/?src=tptw" target="_hplink">New York Times</a></em>. Credit card companies, your wireless service provider, and numerous other firms frequently rely on this tidbit to protect your personal information.

  • Your Home Address

    Publicizing your home address enables everyone and anyone with whom you've shared that information to see where you live, from exes to employers. Opening up in this way could have negative repercussions: for example, there have been instances in which <a href="http://www.huffingtonpost.com/2010/02/17/please-rob-me-site-tells_n_465966.html" target="_hplink">burglars have used Facebook to target users</a> who said they were not at home.

  • Your Long Trips Away From Home

    Don't post status updates that mention when you will be away from home, <a href="http://bucks.blogs.nytimes.com/2010/09/15/dont-tell-facebook-friends-that-youre-going-away/" target="_hplink">advises</a> <em>New York Times</em> columnist Ron Lieber. When you broadcast your vacation dates, you might be telling untrustworthy Facebook "friends" that your house is empty and unwatched. "[R]emind 'friends' that you have an alarm or a guard dog," Lieber writes.

  • Your Short Trips Away From Home

    Although new features like Facebook Places encourage you to check in during outings and broadcast your location (be it at a restaurant, park, or store), you might think twice even before sharing information about shorter departures from your home. "Don’t post messages such as 'out for a run' or 'at the mall shopping for my sweetie,'" Identity Theft 911 <a href="http://identitytheft911.com/company/press/release.ext?sp=11132" target="_hplink">cautions</a>. "Thieves could use that information to physically break in your house."

  • Your Inappropriate Photos

    By now, nearly everyone knows that racy, illicit, or otherwise incriminating photos posted on Facebook can cost you a job (or worse). But even deleted photos could come back to haunt you. Ars Technica recently <a href="http://arstechnica.com/web/news/2010/10/facebook-may-be-making-strides.ars" target="_hplink">discovered</a> that Facebook's servers can store deleted photos for an unspecified amount of time. "It's possible," a Facebook spokesperson <a href="http://arstechnica.com/web/news/2010/10/facebook-may-be-making-strides.ars" target="_hplink">told</a> Ars Technica, "that someone who previously had access to a photo and saved the direct URL from our content delivery network partner could still access the photo."

  • Confessionals

    Flubbing on your tax returns? Can't stand your boss? Pulled a 'dine and dash?' Don't tell Facebook. The site's privacy settings allow you to control with whom you share certain information--for example, you can create a Group that consists only of your closest friends--but, once posted, it can be hard to erase proof of your illicit or illegal activities, and difficult to keep it from spreading. There are countless examples of workers getting the axe for oversharing on Facebook, as well as many instances in which <a href="http://www.huffingtonpost.com/2010/08/16/arrested-over-facebook-po_n_683160.html" target="_hplink">people have been arrested</a> for information they shared on the social networking site. (Click <a href="http://www.huffingtonpost.com/2010/07/26/fired-over-facebook-posts_n_659170.html" target="_hplink">here</a> to see a few examples of Facebook posts that got people canned.)

  • Your Phone Number

    Watch where you post your phone number. Include it in your profile and, depending on your privacy settings, even your most distant Facebook "friends" (think exes, elementary school contacts, friends-of-friends) might be able to access it and give you a ring. Sharing it with Facebook Pages can also get you in trouble. Developer Tom Scott created an app called <a href="http://www.huffingtonpost.com/2010/05/24/evil-facebook-app-exposes_n_587144.html" target="_hplink">Evil</a> that displays phone numbers published anywhere on Facebook. <a href="http://www.huffingtonpost.com/2010/05/24/evil-facebook-app-exposes_n_587144.html" target="_hplink">According to Scott</a>, "There are uncountable numbers of groups on Facebook called 'lost my phone!!!!! need ur numbers!!!!!' [...] Most of them are marked as 'public', and a lot of folks don't understand what that means in Facebook's context -- to Facebook, 'public' means everyone in the world, whether they're a Facebook member or not."

  • Your Vacation Countdown

    <a href="http://finance.yahoo.com/family-home/article/110674/6-things-you-should-never-reveal-on-facebook" target="_hplink">CBSMoneyWatch.com</a> warns social network users that counting down the days to a vacation can be as negligent as stating how many days the vacation will last. "There may be a better way to say 'Rob me, please' than posting something along the lines of: 'Count-down to Maui! Two days and Ritz Carlton, here we come!' on [a social networking site]. But it's hard to think of one. Post the photos on Facebook when you return, if you like. But don't invite criminals in by telling them specifically when you'll be gone," MoneyWatch <a href="http://finance.yahoo.com/family-home/article/110674/6-things-you-should-never-reveal-on-facebook" target="_hplink">writes</a>.

  • Your Child's Name

    Identity thieves also target children. "Don't use a child's name in photo tags or captions," <a href="http://www.consumerreports.org/cro/magazine-archive/2010/june/electronics-computers/social-insecurity/7-things-to-stop-doing-on-facebook/index.htm" target="_hplink">writes</a> Consumer Reports. "If someone else does, delete it by clicking on Remove Tag. If your child isn't on Facebook and someone includes his or her name in a caption, ask that person to remove the name."

  • Your 'Risky' Behavior

    CBSMoneyWatch.com <a href="http://moneywatch.bnet.com/saving-money/blog/devil-details/6-things-you-should-never-reveal-on-facebook/2360/?tag=content;col1" target="_hplink">writes</a>: <blockquote>You take your classic Camaro out for street racing, soar above the hills in a hang glider, or smoke like a chimney? Insurers are increasingly turning to the web to figure out whether their applicants and customers are putting their lives or property at risk, according to Insure.com.</blockquote> There have been additional <a href="http://www.huffingtonpost.com/2010/02/22/facebook-twitter-users-co_n_471548.html" target="_hplink">reports</a> that insurance companies may adjust users' premiums based what they post to Facebook. Given that criminals are turning to high-tech tools like Google Street View and Facebook to target victims, "I wouldn't be surprised if, as social media grow in popularity and more location-based applications come to fore, insurance providers consider these in their pricing of an individual's risk," <a href="http://www.huffingtonpost.com/2010/02/22/facebook-twitter-users-co_n_471548.html" target="_hplink">says</a> Darren Black, head of home insurance for Confused.com.

  • The Layout Of Your Home

    <a href="http://identitytheft911.com/company/press/release.ext?sp=11132" target="_hplink">Identity Theft 911</a> reminds Facebook users never to post photos that reveal the layout of an apartment or home and the valuables therein.

  • Your Profile On Public Search

    Do you want your Facebook profile--even bare-bones information like your gender, name, and profile picture--appearing in a Google search? If not, you should should block your profile from appearing in search engine results. Consumer Reports <a href="http://www.consumerreports.org/cro/magazine-archive/2010/june/electronics-computers/social-insecurity/7-things-to-stop-doing-on-facebook/index.htm" target="_blank">advises</a> that doing so will "help prevent strangers from accessing your page." To change this privacy setting, go to Privacy Settings under Account, then Sharing on Facebook.

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