One of the other people that I had the chance to meet at mesh07 was John Jantsch of Duct Tape Marketing. During his panel discussion with Maggie Fox (who said she liked my shoes) and Jen Evans, someone asked a question about why he blogged and about the return of investment on blogging. John's answer was probably the best that I have ever heard to this question. He said that when he first started blogging, he didn't think anyone would ever read it. Blogging gave him a chance to gather his thoughts, and forced him to research some of the topics he was writing about. As a result, John said that he became a better writer, and was able to speak more confidently about what he was writing about.
Those two reasons alone are enough for most people to start blogging. While it might be possible to make similar improvements by just keeping a journal, a blog forces your thoughts and writing into the public sphere. You become much more accountable for what you've written, and as a result are more likely to take it more seriously.
Another point that was brought up in the same panel discussion (I don't know who said it, but I'll attribute it to Jantsch just because I like his good-natured attitude) was that we don't try and measure the ROI on taking a client out for lunch. A meeting like that might not result in anything tangible at that moment, but its about building relationships. The same goes for an organization's blog. It is unlikely that launching a blog will result in a huge increase in sales, but by building a relationship with
I'm not saying anything new here but, like John Jantsch, I'm just writing it down and posting it to secure my own thoughts on the matter.