Shoutbox

Hm...
I think chat is more like an action, somehwat like the word talk:
"I talk with blah" "I chat with blah"
And "Start a talk with blah" sounds weird, instead something like "Start talking with/to blah" or "Start chatting with/to blah" sounds better.
Anyway, "a chat" is not an object, and in my eyes not valid.
"a conversation" sounds a lot better to me...