Sweepsify.com uses Sur.ly and now you can get it working on your domain too!
Works on all modern platforms
Sur.ly helps keep outbound links under your control
Sur.ly will replace user-posted outbound links with its indirect safe links to the same target pages, so if users follow such links they'll be protected against possible malware, adult or pirated content (that might appear on a target page) with interstitial page. Also, Sur.ly adds its customizable toolbar to the top of any target page to let users stay in touch with your site and stimulating them not to slip away from your site but return for more interesting content. Webmasters can set up Sur.ly on their domains to generate safe links on their own subdomains avoiding any third-party sites.