Could it just be the sheer level of traffic here? This is the most hugely-populated and widest-ranging forum I've ever been on. Prior to this I've only been on a few small invitation-only boards, where it's far easier to keep up among fewer threads by fewer people. If I find a thread I can relate to here, but can't think of an immediate reply, I have to bookmark it; if I don't, many more threads have usually come in on top of it by the next time I sign in, making it hard to find the one I was after.