I'm probably about as paranoid as anyone can get on such matters. I have never told anyone at all the exact name of this site, or posted any image of myself, or used my real name. But i guess if someone was intent, they could google search all the mental-health sites for certain "identifying" words/phrases (which i may have used from time to time), but still it'll be looking for a needle in the haystack.
That's one thing that i really hate - real-world people knowing any of "my private business" (my ways, secrets, issues, etc). So, yes i'm absolutely paranoid about my "privacy", but that goes along with the "territory".
And the same applies to all others sites. I have only ever i think put up one photo on a site, but i altered the contrast right down, "painted" over the background, altered the hues, etc.
But the good thing about this paranoia, is that i'm pretty much "rock-solid" insofar as being immune from identity theft