How about "Hello" followed by the question?
IM manners are a cause of annoyance for me too. I especially hate most people's inability to use several paragraphs within one message, instead sending a staccato of several messages.
That. Just go: "Hi there, I was wondering..."
Also I'm guilty of this "spam" as well...
Shift + Enter is too difficult for them.
... and mostly only realize there is this option when it's already too late