I just ran into this little "gem" today while doing normal internet browsing.
The first thing I noticed was sluggish response between link clicking and page loading.
Second thing I noticed was certain key words on almost every web page I visited were underlined and linked.
Third thing was text ads appearing in Facebook as "ad not by Facebook".
Running my mouse over the "ad not by Facebook" revealed the name "Coupon Companion" ... which I never knowingly installed.
A Sypbot scan turned up nothing, so I looked for "coupon" on my hard drive.
* 2 files turned up as "Coupon Companion" in "Program Files" and "AppData/Local" ...
* 2 more files turned up as "couponcp-a.akamaihd.net" under "AppData\Roaming\Macromedia\Flash Player\#SharedObjects" and "AppData\Roaming\Macromedia\Flash Player\macromedia.com\support\flashplayer\sys"
* One registry key turned up under "Coupon Companion"
* One Firefox extension turned up as "Coupon Companion"
I deleted everything, which seemed to stop the ads, however "couponcp-a.akamaihd.net" reinstalled it's self ... so now I need to figure out what the heck is auto dropping the files.
*[Update]*
After digging around I found that the "couponcp-a.akamaihd.net" folders are from unrelated flash cookies.