I think it's fine to tag out, but it's also nice to put up the occasional post. Some people are uncomfortable contacting strangers OOC. They might want to develop CR but can't because a) the above and b) you don't tag their characters.

Be very careful that you spread it around if this is all you do. I've seen more than one person only tag one or two other RPers characters in an entire game. Anyway, I wouldn't worry about people not tagging your post. Sounds like you've already established CR. My theory as another LCW lover is if you tag them, they will come.