• How to Use StumbleUpon for Your Business: The Definitive Guide
  StumbleUpon also allows you to “discover” new sites. In your regular browsing experience, you might find a site that you think would interest other people. The “thumbs up” icon works for all sites, and that is how new sites get into the database of StumbleUpon pages that are served to the end user during their stumbling session. When you “thumbs up” your site and it hasn’t yet been submitted.
  in Public bookmarks with guide stumbleupon

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