Bloggers is a highly heterogeneous group so it's important to understand the true addressable market (how many on wordpress, how many write content that is review-worthy, how frequently do they write, do they have their own domain, are they trying to make money, etc etc). Otherwise, it's akin to saying "my market is internet users".
Technorati reports 112M blogs, most are not super talented like PG or other top bloggers (OK essayists). I count my self in that category. So there's quite a few that would fit my target market.