A lot of my friends/classmates all use AIM and MSN Messenger to communicate. It rolls chat, file sharing, and even a digital bullitin board or answering machine all into one, especially with away messages in AIM. Quicker than email.
So, it may be harmless. But it also may be a problem. Thats something only you and your wife can decide.
Is she actually addicted? If she is, thats generally symptomatic of deeper psychological issues that might need to be addressed.
It's just that the time rolls by when she's doing it, like when I play computer games. I don't really feel ignored at this point because I am working while she is doing it.
I kind of threw "addicted" into the title there to get peoples' reaction.
If I was trying to send romantic signals to her and she couldn't break out of her chat-haze, THAT WOULD BE A PROBLEM. So far it hasn't happened.