I just set my default status to "away."
Which is right most of the time, because I just leave my computer on all day.
I put it on standby (which signs me out) 99% of the times I leave my computer and I know I will be away for at least more than 5 minutes.
No I mean when I want to talk to someone with "Online" as their status, I will consistently poke them until they talk to me.
I usually do that even if their status isn't set to online haha
You in paticular don't even need to be using an IM client to consistently poke someone.