I know the moderator of frumteens (the original one), and he is a very chashuv Talmud Chacham. I know that he got overwhelmed by the site and brought other moderators aboard; and I’m certain that those were people he trusted.
Naaleh.com has a tremendous variety of shiurim, and it’s free. (although they do ask you for a donation every time you pause a video!). I’ve put lots of Naaleh shiurim onto my mp3 player.