Yes, I use them a lot, but find the organizing tools pretty lacking. E.g. I program in Python and keep a bookmark for many Python modules in alphabetic subfolders so that I can quickly jump to the docs. It's rather boring to maintain this setup. I also dance tango and I'd love to bookmark many Youtube videos but here the tools are really primitive: there's lots of ways to organize this (by type of video, dance style, by principal figures, by dancers -- sometimes more than one couple -- by music maybe) and no easy way to do anything other than a silo of "all things tango".