There have been a few times - reading blog articles or pieces of code - where I've been tempted to write to the author to show some appreciation, but have shied away from it thinking they might take it as creepy or parasocial. It wouldn't, of course, I can write a short "hey, I really liked this" note without coming across like a maniac, but a little voice always stops me short. I'll try to ignore it in future :)