It is the ads changing at the top of the page. Another reason there is more "loading" going on is because many of the ads now have several "slides" per advertisement. Each of these slides has to be transferred to your computer so they can be displayed on your screen. With several of the ads having several "slides" it is utilizing alot of CPU resources, mine went from 90% down to 10% just when I closed TY. And that was with 5 other Internet Explorer tabs and Itunes open. I have noticed there is one advertisement in general that is taking up alot of bandwidth and slowing things down. I don't remember which one it was though.
rlbock,
If you have closed out all instances of TY open it is impossible to still be getting traffic from TY, once the HTTP session is closed that's it, it can't be started again without the user initiating it.Your computer has issues if it is resetting all by itself, TY cannot make it do that.