This might just be my paranoia, but I was interested in using Magic Actions for Youtube, and I noticed that it's not anywhere in the mozilla addon listing. I found a mozillazine forum post about it and they said a year or two ago that they were going to have it added, but they hadn't back then because verification took a while and they are sometime pushing out updates daily. Since then they still haven't put it up. So, there's places all over to get it, including their own website, but out of habit I haven't added anything to my addons that wasn't verified by an official source. I couldn't find anything in official reviews either, other than a PCWorld affiliate doing a blurb about it.
The Chrome App store version seems ok, but since they've let some stuff slip through before, I couldn't be entirely sure it was safe. My main concern was when I did an isolated test, I noticed the options button takes you to their webpage, instead of being self contained. After uninstalling it (and as far as I could tell I removed all traces), shutting Firefox down, then restarting and reinstalling, I noticed that it remembered my settings. -That- is the only thing that worried me, since it appeared like it was storing something remotely. I poked around in the xpi but I'm not familiar with building addons so although I found a few places where options could be stored or references to where they could be stored outside the addon, they all appeared defaulted or blank.
So, has anyone used it for an extended period of time and not had any adverse results? Or did I just overthink this way too much? It was just the lack of information on my concerns seemed odd, but then again I doubt most people think about such things these days.