Everybody is doing it, and in a year from now, twice that many people will be doing it.
When email was new, everybody loved a good monthly e-newsletter. That was 10 years ago. Today, your clients want information now -- not at the end of the month. Blogs deliver news right away, right when the client needs it.
It's not enough just to blog; your blog must be updated daily with interesting content for readers. Owning a quality blog will quickly position you as a Market Expert to your clients and partners.
A blog showcases your personal brand to clients in the medium they research most -- the Internet. Because blogs change daily, your "expertise" is constantly reinforced.
Blogging is much less expensive than your existing marketing methods. There's no stamps to buy, no marketing assistant to pay, and no letters to fold and stuff.
Better Listings On Google. Blogs are much more likely to get indexed by search engines than Web sites because they change so frequently.