Yahoo Messenger Upgrade a Yahoo Search Trojan Horse?

Yesterday I was prompted by Yahoo Messenger to upgrade to a new version which included a security upgrade. I almost accepted the upgrade until I looked at the box on the right of the screen.

As well as the newest version of Yahoo! Messenger, you'll also get these helpful Yahoo! tools and services.

Their toolbar, changing your existing homepage to Yahoo.com and making Yahoo your search engine.

I'm sure plenty of people don't pay attention and click away only to find their MSN or AOL homepage is gone. It would be nice if they put check boxes on that page so it was easy to opt-out of these other "upgrades."