Some ramifications include:
- If you chat about your work, they can sell it to your competitors
- If you chat about some co-worker/friend/lover/random person on the street who's driving you nuts, they could sell transcripts to that person, giggling the whole time
- If you discuss a creative enterprise (say, a comic strip), they can make a commercial featuring your discussion of that creative enterprise
Now, realistically speaking, they probably won't do any of that stuff. But the fact that they're setting it up with the idea that they could, is less than encouraging.
Bottom line: watch what you type, your chat program is listening.
Edit: AIM strikes back! Their claim is that the "we own it all" clause refers only to public forum posts and the like. We'll see...