del.icio.us

This is one step further than just bookmarking a webpage, as you can also gauge how useful the page is by the number of saves people have done.
It's quite cool I think, the internet is rapidly evolving into a community of people that help each other out... and the quality of pages are assessed almost subconsciously... kind of like you would be drawn to a cafe with a lot of people in it rather than an empty one across the street. There would be a reason why some pages were saved more than others...

I checked out RSSCalendar.com http://www.rsscalendar.com/rss/
It had been saved by 1281 people and it looked really practical as well. Most people just left comments describing the function of the page, but some actually mentioned that it was a shame they hadn't found it earlier.

I think it's great as well that you can open your list of saved pages anywhere you like, as I use two different browsers on my computer and sometimes I find it pretty frustrating when it comes to locating my bookmarked pages.