Portaportal.com
I love this bookmark manger. It’s easy to use and, most importantly for students, a very clean and uncluttered look. They have now added the option to use it without any ads. The price is quite reasonable too. $15 per year for 5 accounts.
We only have one account so far but have talked about adding two more: one for parents and another for staff.
You can see the links for MLBV and Howard Elementary portaportals on the right.