Merriam - Webster using distaseful ads

When I used to think of the dictionary folks at Merriam - Webster a scene of an refined, well kept library came to mind. A high class organization with the sole focus of keeping our lexicon. I used to user their online dictionary all the time but moved to either dictionary.com or tfd.com. Today, I was doing a quick comparison using m - w.com again and was remined of one of the reasons why I switched. After looking up the word, I noticed that I got a pop - under ad (the kind that you might not notice until you close your main browser window). This is despite the fact that I use Firefox and have it setup to kill all those types of ads. This means that not only is Merriam - Webster using pop - unders, which are one of my least favorite types of ads, but they are specifically working around pop - up blockers. For a mainstream (not porn) website, that's about as low class as you can get.