If you sent me an instant message and wondered if I've received it, or if I'm going to respond, you might want to consider the following:
I use instant messaging to chat with people I already know, or for other people to contact me about things genuinely related to the work that I do, or about something on my website.
I do not have any interest in being chatted up by strangers, nor chain messages, rumours, or warnings.
Chances are that I will completely ignore any message that seems contrary to my interests in instant messaging. I will not add people to my list before working out whether I want to, nor immediately authorise others to add me to theirs.
I may not respond instantly. I may be busy, I may be away from the keyboard, and the instant messaging program waits a few minutes before automatically declaring that I'm away.
If you're an old friend trying to work out if you've found the right person, have a look in my personal information section to work it out. There's more, in there, than is written in the profiles that go with my instant messenger accounts.