Rated 3 out of 5 stars
Service has been revived. dnsmadeeasy.com has assumed responsibility for hosting & maintenance of the LongURL.org service. See http://twitter.com/DNSMadeEasy/status/12212203681, etc.
Still supports the most URL shorteners, but hasn't seen an update in almost 11 months. LongURLPlease is swiftly overtaking this extension in terms of feature-completeness and reliability.