Unless you're chatting to A) Get Off or B) Actually wanting to get involved in some way, a lot of chats will die.
The depth of a person can't really register unless they're truly genuinely interested in you... in which most guys (assuming that's what you mean) just really aren't. So many IM's I've gotten just about fucking and stuff and it dies off...why? Because that's all we have in common for that point in time... and even then, if it's an unwelcomed conversation where it strikes an awkward point, it usually just cuts it off entirely.
My best advice? Just keep typing or trying. Don't wear yourself thin, if you feel you're on a fail kick where all you keep finding is the wrong kind... just stop for then and continue at a later point.