Robin Good: StumbleUpon has recently itroduced "list", a new feature which allows you to collect and organize, in a Pinterest-like fashion, your favorite sites/web pages/resources into dedicated sets.
The new "list" functionality can be accessed from the StumbleUpon toolbar or from within your account.
Lists can be set to "public" or "private" and are fully free to use.
Try it out now: http://www.stumbleupon.com
Via Robin Good