"You can 'clip' anything you want... absolutely anything!"
But it's not perfect.
The hovering thing gets kind of annoying when I can't get the blue glassy rectangle to cover exactly what I want it to cover. I would much prefer to actually have a clipping tool where I could define the clip area myself (like in any photo editing software) instead of the clipper just trying to guess what I want.
I wrote a lot about Symbaloo here. The more I play around with other bookmarking tools, the less I like it. It takes too much time to create buttons, and they're not that visually appealing.
Here's a Pearltree I'm building as a resource to teach digital citizenship in the classroom: