As someone who does media compression pretty much daily, your marketing spiel really came out to me badly for the same reasons. While you can optimize JPGs and PNGs in a lossless fashion, you really can't do the same for audio and video. You might be able to make them smaller without losing (much) perceived quality (aka do transparent compression), but you're still doing lossy compression. Same with converting gifs to videos - while the biggest loss certainly happens in the making of the original gif and while you can get a humongous increase in compression quality, converting it to VP8 is still lossy.
And speaking of which, saying that you can get "1000-3000% faster for some files" is also pretty dishonest. You can pretty much claim those kind of numbers with only one of the many formats you support (and one where you're not doing lossless compression), but the way you word it makes it sound like you could get it for potentially anything.
All in all, I'd really suggest you rewrite the description to be more honest.
Two other things I noticed: I can't seem to select text on the homepage (on latest Chrome). Your icon also looks rather similar to that of Miro: http://www.getmiro.com/