If the board uses Tapatalk at the standard Tapatalk URL than it should "just work". If it doesn't, then if you know the Tapatalk URL, you can tell Owl what that is. I'll update the wiki (
http://wiki.owlclient.com/index.php?title=Add_a_New_Board) shortly on how to do that.
Owl will also use parsers to basically do an HTML scrape of data from boards that don't have Tapatalk installed. Because it's just me (and since Joe is too lazy to help! :shakefist: ) the only parser that ships with Owl is for vBulletin 3.x. This is why you were seeing images and markup when you viewed JUOT in Owl, since Owl wasn't using Tapatalk but was using vBulletin.
I hope to have vBulletin 4.x and XF support before 1.0.