There are few different ways that buzz can be created for products, services, or even blogs I guess. The April 2006 issues of Inc. presents 5 different ways that marketing can be done to help build that buzz to drive traffic or sales to something. The 5 ways are:

1. Words of Mouth - Word-of-mouth marketing is any initiative that prompts customers to talk to other people about a product or service.
2. Viral Marketing - Promoting products or services through messages and video spread by consumers via email. I would consider having people post comments about your blog on other blogs viral marketing.
3. Buzz Marketing - Winning attention for products by putting them in the hands of celebrities. I am currently trying to line up Jenny McCarthy to promote my sites :)-
4. Influencer Marketing - Targeting the connected or cool people that lemmings most likely follow.
5. Stealth Marketing - Marketing disguised as something else.

There are lots of ways these can be applied to blogs and niche content sites. The trick is figuring out how to do it that no one else has tried.