Actually, they're using the agreement as a weapon against MS. It expired in January or so, and they reupped for a year in order to argue in court that MS is strong-arming them into not promoting their own browser.
Indications seem to be that they'll switch early next year, which gives them time to do the 6.01 bug fix/optimization release before giving out insane numbers of copies of the browser to new users.
This reminds me of the old Gartner Group studies of browser usage... Before they stopped tracking browser usage, they indicated that almost 50% of MSIE users said they used it because AOL gave it to them. Apparently, more people use what their ISPs give them than what their OS vendor gives them.
Not necessarily. AOL is the biggest dog in the pack, but there are lots of ISPs that ship MSIE.
An interesting question is how MSN Explorer fits in. Will MS's increased ISP push alarm other ISPs into dumping their MS deals?
And how concerned is MS with the browser market? Controlling the most widely used browser is nice, but it hasn't produced a lot of concrete benefit for MS so far.
And then there's the embedded market. This seems to be going overwhelmingly to Mozilla, but it isn't a huge market so far, and we don't know for sure that it ever will be. Things are getting interesting lately.