FoodTreeMD: In spite of a shift to online media, I'm not sure that building followers is much different now than it was years and years ago. You need to engage with individuals, build their trust in you, and they will evangelize for you. These are your top supporters. Plastering your URL everywhere WILL help but it will probably be more of what @timethief mentioned -- other people trying to use you for their own promotion.
That said, there's nothing wrong with plugging your blog on the forums or elsewhere. Just tell people why they should care about you and visit instead of any of the other sites. Then, make the content good enough that they want to come back.
I offer all the standard recommendations -- Twitter, Yahoo! Answers (e.g. quote your own URL as the resource you used to answer a question in their forums), WordPress forums, blog directories, WebMD (for your speciality in particular), and other trade and general interest communities.