I dont like using chat boxes on forums, because i think it takes away from activity on forums itself..but it seems to work fine on this site..Since people have other reasons to post.
If I'm on skype, and a chat died..I'd just try to bring up something related to things we're into, or some news I've heard, and usually people react to it, and we start having a convo.. Just saying hello, and how was your day works wonders too.
Never talk about yourself..or what you just did though. i've had bad experience with that. nobody cares if you just had KFC, or your mom just disconnected your internet lol.