StumbleUpon www.stumbleupon.com Review

Overall Rating

Free; informative and educational; works with a variety of browsers; fun for all the family; tons of interesting sites.

Occasional server issues; addictive; a few weirdos here and there (although you can choose to block them).

Updated review - September 9th 2005. Updated to prove that this is my review... I posted it here first and then in the Mozilla add-on assessment page. I am now being accused of plagiarising my own work - which is kind of difficult, no?
Also available at the following sources (all of which are MY accounts):
http://www.ciao.co.uk/stumbleupon_com__Review_5528003
http://www.reviewcentre.com/review165912.html
Stumble Upon works on all browsers except Safari, IE for Apple Mac, and Opera. Published by Mozilla, it is a free add-on which lets you browse, review, and share a huge range of sites, while meeting new people.
Choice and variety are the best aspects of StumbleUpon (www.stumbleupon.com). The underlying idea is that you select topics that interest you. You then use the stumble button to visit related random websites, which are reviewed by other stumblers. You can either agree or disagree with their ratings and post your own comments; or you can simply move on to the next site/topic. There are hundreds of special interest groups here, where you can 'meet' like minded people.
StumbleUpon is community based without being claustrophobic, as you can interact with others as much or as little as you choose to. Your page can be used as a normal blog: you are not obliged to rate any websites if you don't want to, or if you aren't interested in them. It's worth remembering though, that the growth of StumbleUpon's database relies on input from its users. Submitting interesting, high-quality sites also improves your rank as a top stumbler, bringing your recommended sites to the forefront of the database.
Although the site is free for all to use, you can gain extra access by paying £11, or $20 per year. The benefits of upgrading include the ability to turn off advertisements, unlimited stumbling within favorites of your friends, and the option to create new interest groups. Unless you want an exceptionally high level of involvement within the site's community development, upgrading isn't particularly useful: you can find links and contacts almost as easily by registering for free.
I highly recommend this educational, innovative toolbar: It is the most informative browsing extension I have seen so far. It is useful for people of all ages, and is a lot of fun! The only reason I have NOT given StumbleUpon 5 stars, is because it is currently having appalling server issues. It was running ridiculously slow yesterday, and now has stopped working completely. This is rare, though. Although the program has occasional bugs, these are usually solved quickly. In terms of Spyware: I have not encountered any Spyware myself within StumbleUpon, nor have I been told of any such problems by other regular members.