Theres still a strong trend in angel investing to remain quite and lay low. Thats changing with the new guard (sacca, lindzon, dave, etc) and its starting to trickle down to other parts of the country.
Soon enough I think people will see the benefits of being visible and having good deals come to you, like Fred and AVC....
The problem is that you have to filter out the 99.5% of non good deals, and most angels don't have the time/resources/interest to do that. (That's why they come to YC- pg does a lot of prescreening for them)
Besides, what's the likelihood you'd invest in a random person that comments on your blog? I'd trust that person only slightly more than I would a Nigerian scammer.
Soon enough I think people will see the benefits of being visible and having good deals come to you, like Fred and AVC....