Starting today I see lots of words highlighted green that link me to advertisements. Is this a new thing or is my computer messing with me?

Just me, sorry! My computer did some updating today; I cleared all of my cookies and such and it's gone, nevermind.

I had that happened once; my husband told me it was malware, and then went about cleaning it up. Not sure how he fixed it, but it sounds like you've got the same "infection".