The typical blog post is written, shared, indexed, and quickly forgotten to be replaced by newer blog posts about the same topic or by the same author.
You can cross your fingers all you want in the hopes your best-written piece is shared by more people or indexed by more search engines than in the past, but crossing fingers will not boost a blog post's value if nobody else believes there is value. For the same reason a video creator can not gauge how many people will view a video before it is created, a blogger can not predict the popularity of a post. While there are ways to resurrect and recycle the majority of old blog posts, there are also the few that survive the above tests and remain actively visited because of a high search engine index rate or limited online information.
Take a look at my most popular blog post article of 2009, for instance, wherein I share screenshots explaining how I hacked a popular Facebook game. As of today, my post on the Bejeweled Blitz game has been shared 59 times on Facebook and 3 times on Twitter, not to mention being the recipient of 23 comments.
The popularity of a blog post goes beyond comments and shares, though; you must also remember the ubiquitous Google, let alone other search engines. Based on a myriad of reasons known collectively as Google Page Rank, if a blog post is viewed so many times and commented and linked to so many more times, Google considers the information timely and valuable -- and will continue to rank it high in a keyword's results page until nobody else clicks on it or comments on it. Since I published the article in July 2009, it's seen 1-2 comments every month. Google likes it.
Querying a Google Analytics report (that excludes my own visits) on the most popular content viewed between January 18, 2009 and January 19, 2010, the Bejeweled Blitz article is most popular, with 91,018 pageviews across 70,662 unique visitors. In comparison, here's an image of my top 5 viewed articles over the past year:
Over 95% of those 70,662 visitors entered the page directly from a search engine or a referral link, with Google responsible for 60,869 unique visits. People typed a combination of 9,175 keywords to reach the page. Evident from over a dozen unique visits to the page while I typed this retrospective article, Google continues to share its value with you and your Facebook peers.
I challenge you to write your next blog post from the perspective that you are the Internet Newspaper. Write succinctly but clearly. Share a fact, a tidbit, or an image that nobody has seen before -- but that everybody wants to see. Think to the future, but write for the present. Most of all, be yourself and write like the passionate scribe you decided to be when you created your first post. Don't worry about comments or shares. Don't worry about page rank. When you reach the gold nugget, savor the moment and share with all of us your tips for success.
I don't know why the Facebook article remains popular. I don't know why people still view it, for there are surely comparable articles online. I have a hunch, though, for its success, and that is because I likely wrote what I wrote before everyone else wrote what they wrote; and in Google's eyes, original ideas mean something.