Just to weigh in on this from a web archivist's perspective, shortened URLs introduce another point of failure in the long-term accessibility of web resources. For this reason, the Internet Archive hosts a project called 301 Works (http://www.archive.org/details/301works), whose purpose is to archive the shortened URL-to-original URL mappings in the case that service providers disappear. A recent study (http://ws-dl.blogspot.com/2011/06/2011-06-23-how-much-of-web-is-archived.htm...) by web preservation researchers at Old Dominion University also found that among randomly-sampled links from DMOZ, del.icio.us, search engines, and bit.ly, the sites linked from bit.ly were least likely to be represented in at least one Web archive. ~Nicholas Nicholas Taylor | Information Technology Specialist | Library of Congress Web Archiving Team<http://www.loc.gov/webarchiving/>