Bit.ly preview extension makes it easy to know where bit.ly link goes to, especially necessary on sites like twitter where malware authors can spread malicious links through bit.ly links, sites like URL X-ray and Untiny retrieves original URL for a shortened link, but those works only for individual URLs. Is there a possibility to preview /know almost every shortened URL goes to in twitter, yes.
LongURL service automatically expands short URLs to original URLs. Currently LongURL expands shortened links from 330+ URL shortener services includes goo.gl, tinyurl and bit.ly. LongURL currently available as Firefox and Chrome extensions.
LinkPeelr is another URL expander available for Chrome as extension that takes a URL and peels it to show you the URL that you’ll actually will be taken to.