An interesting story came into my radar this week when one of my sources told me of problems some chap had when installing Yahoo Messenger with the auto-update function enabled.
Turns out, apparently, that this chap discovered immediately that all his web link associations were changed from Firefox, his default system browser, to IE7 and then a rather confusing error message was thrown up informing him of this change and offering to 'fix your settings' or 'accept changes.'
Now this is where Yahoo would appear to have got rather sneaky and dealt the low-blow. Thinking that something is interfering with your browser settings you would most likely not want to accept the changes, instead you would go for the fix problem route. Which is what chappy did, only to discover his homepage was now pointing to Yahoo by default and IE was defaulting to Yahoo for search as well.
Sort of brings a new meaning to search engine optimization huh?