I got this add-on to make reading tech blogs and foreign news easier to understand. I needed help with some of the 'common knowledge' acronyms. This thing ROCKS! Sometimes I check it out on some very uncommon science and medicine acronyms and sure enough the definition is there!! I've added a few that weren't there, but I almost never get that privilege :)
A search using the excellent acronym definition website acronymfinder.com (I've been using it for years). Works perfectly, with the only advertisements being the inoffensively-presented line ads at the website.
I like the idea, but it puts a bunch of "sponsored links" at the top of the results. You have to scroll down the page to get to the real search results. I believe this is set up by the same people who provide All the internet. Looks exactly the same. No thanks.