Seconding what Ryan said— I love your characters, and I think you have a real talent for carrying each unique voice, and keeping the threads lively and interesting. But you drop so many threads that I find I've stopped tagging you in the first place. I've gotten the feeling from the thread-dropping that you don't think my characters or threads are interesting enough to continue, so I felt a little bad imposing them on you and stopped trying.

If it's just a matter of running out of things to say, I definitely have that trouble too! Sometimes I get myself in the mindset of "okay just tag this with SOMETHING"; it might be a little inane or empty, but if the thread has been good so far, a brief lapse in that won't hurt anything— keeping the thread going means it has the chance to pick back up into something interesting again. Dropping it nulls the chance of that better than a crap response!