It seems like it's a new bug introduced in the new nightly r40220. When I load a Flickr page, such as: http://www.flickr.com/photos/keehun/3223960583/in/photostream/ it shows nearly a fully blank page. When I drag the "picture" it can see it following the cursor like it should. When I open this in Safari (not nightly webkit) then it loads fine. It rendered fine until this new nightly revision.
*** This bug has been marked as a duplicate of 23524 ***