Where has the SearchMe extension for Safari and Chrome come from? Again, today, I found out that my default search engine has been changed to "Yahoo", which is weird as I didn't do that. 

This is the second time it happens, and I found out there is an extension named "search me" is installed both in safari and chrome. Where is this stupid plugin comes from?  I don't remember I install it.

Some other guys also have this issue: Apple Support Communities thread
The current versions of uTorrent and bitTorrent, as of July 2013, bundle the SearchMe extension in their package installers.

Shady.