If I were still teaching Trademark, I could make something of JewTube. It's not quite an exam question, but it's at least a good class discussion. Is it a trademark violation? The chance of confusion is low. YouTube has considerable fame, however, so actual likelihood of confusion may not be required. There's clearly some overlap in what the sites do: serve up little movies. And the parody defense may be inapplicable, because JewTube does not appear to be a parody — it seems to be serious, for all that there's not much content there, and what there is won't detain you long…
But maybe it's not commercial, so the site survives, so long as it never runs a banner ad.
Anyway, I don't teach Trademark any more, so I don't have to worry about any of it, except why the site is so lame.