https://addons.mozilla.org/en-US/firefox/addon/8636 there are many URL shorten service out there, since it obscure the real url of a website, there are also many people abusing it to defraud you. LongURL Mobile Expander will show the real destination when you mice hover the shortened links. A good way to be safe. PS, This service is provided by longURL.org service. There is user js file with greasemonkey can do the similar job too.