Mostlt Bookmarking site in the list are zero PR sites and I think, these sites are not good for bookmarking untill these sites gain at least one PR. But Thanks to you for sharing a good information with form members.
As for me, I don't have enough hours in the day to cope iwth the deluge from Pinterest! And then I have to keep up a growing presence on Facebook, Twitter and Google + and dabble a little bit on StumbleUpon. I can't cope with more. I used to do a bit more sites when I started, but these have gobbled up all my time, and they are giving me the results I want. So, why go chasing after more? If you do a few and do them well, you'll get the benefit you need. No need to wear out going after every site that is out there!