Online services like social bookmarking sites are defined as bookmarking storing on the servicers of clouds which can be accessed from anywhere.
To create bookmarks one has to register on these websites, which can be tagged in multiple categories. Just check out these free social bookmarking sites 2020:
(1) eduhub.io
(2) diigo.com
(3) pinterest.com
(4) scoop.it
(5) mix.com
(6) instapaper.com
(7) sitejot.com
(8) folkd.com
(9) plurk.com
(10) pearltrees.com