I think Flickr discussion group is a great place to promote. By promote, I mean gently and organically bring up this site, not in a spammy way. I've learned a lot from the Flickr photography groups. However their blog comment styled of formatting is very hard to find related questions, tags, best answers.

A few Flickr groups I love:

http://www.flickr.com/groups/nikondigitallearningcenter/discuss/ http://www.flickr.com/groups/nikon_d90/discuss/ http://www.flickr.com/groups/critique/discuss/

There are many many others. These groups have a lot of members and are fairly active.

So if you're a Flickr user, may be try to spread the word in your fav groups.