Anne Zelenka, lead writer for Web Worker Daily, considers instant messaging as "an ideal platform for making a pest of yourself" and has summed up several ways to annoy the hell out of your contacts. My selection:

Disregard any presence indicators such as busy or away. Your needs are more important than anyone else’s and you know that some people regularly set their IM status to busy or away even when they’re working on unimportant stuff.

But don’t set your own presence indicators when you’re busy or away from the computer. That way people trying to get a quick answer from you will feel first hopeful and then frustrated.

Don’t pause to give the person a chance to respond. Stream-of-your-own-consciousness is a great way to show that you matter and your conversational partner doesn’t.

Expect instantaneous replies because when someone is IM’ing with you, s/he should only be IM’ing with you, not doing anything else. You should expect her to close down all other chats, turn away completely from whatever she was doing, and give you her full attention.

Don’t ever use correct capitalization or punctuation. ur 2 kewl 4 dat!

Expect that IM conversations will always be like phone conversations, with a definite goodbye at the end. If your colleague hasn’t signed off, that means the discussion is still going, so keep on typing messages even if you’ve found out what you need to know.

Send large files without asking whether it’s okay. You know better than anyone what people need.

Sprinkle emoticons liberally into your messages. One in a sentence is good, two is better, three provides maximum distraction and visual harassment.

Try out all the abbreviations you can think of. Learn new ones every day, so you can be as compact and opaque in your communication as possible. Don’t stick with the ones everyone knows–lol (”laughing out loud”), brb (”be right back”), and np (”no problem”). Try out some new ones, especially on people you know are likely to be unfamiliar with them. How about ptmm (”please tell me more”) or wdalyic (”who died and left you in charge”) or issygti (”I’m so sure you get the idea”)?