Not too long ago, blogs served as little more than blow-by-blow descriptions of individuals' daily activities. Today, though, these are used with varying degrees of success by companies, celebrities, and individuals. Particularly those in real businesses.
Blogs can be a powerful tool, because if implemented correctly these time-users provide a way to communicate with customers and prospects that in all cases is not subject to a media filter. We have seen a wonderful example of this via the blog of Sun Microsystems' Jonathan Schwartz, who is frank and pleasant--and unscripted (at least I think so).
Conversely, if a company or celebrity attempts to fool the customers by staffing out their "official" blogs, they better be prepared for some blowback. People -- especially blog participants-- aren't stupid and if anything are usually more keen to out the fake bloggers, and there are consequences ahead for treating them as though they are nothing but PR.
You can be quite successful in getting you own blog running--see the video I did of an interview on CNN that explains why competition is pretty slim these days. It's all about finding a content niche and identifying what your audience needs from you.
Here is the clip of where I talked about all of this and more on the topic of fantastic blog making.
More fun on Twitter @laermer.