For instance, "cash" shows "prizealert.com-ni.net" as the link with an advertisement for prizes won.
Do a malware check with some malware scanning programs on the Windows computer.
You need to scan with all programs because each program detects different malware.
Make sure that you update each program to get the latest version of their databases before doing a scan.
You can also do a check for a rootkit infection with TDSSKiller.
Okay, so here's what I've discovered. As I said above, I installed an emoticon add-on that started with a "Q". I also installed another emoticon add-on called "Bandoo". I had already de-installed "Q" but left Bandoo. There was another symptom that only seemed to apply to Facebook. That was ads popping up between items in my timeline. Now that I've de-installed Bandoo, I no longer get those ads and some, not all, of the "linked" words on other pages have gone away. I did not reboot after the de-install of Bandoo, only killed and restarted Firefox and IE. Hopefully, the next reboot will remove this issue entirely. Thanks for the help, cor-el. Apparently, it wasn't spy or malware but nefarious money making by the "free" add-on software.
Well, the reboot didn't accomplish what I had hoped. The ads are back in Facebook and the linked word(s) can be seen in the example. Hopefully, it will show up larger than I'm seeing or you will be able to enlarge it. The linked word(s) are in blue and underlined. If you hover over them, a box pops up with "Click to continue > By Text-Entrance".
Check the Add-ons / Extensions in Firefox for the savesales 3 extension, if it is installed delete/remove it.