Are URL shorteners building domain authority everytime someone uses a link from their service?

[Jay.Neely]

My understanding of domain authority is that the more links pointing to any page / resource on a domain, the greater the overall domain authority (and weight passed from outbound links on the domain) is.

Because URL shorteners create links on their own domain that redirect to an off-domain page but link "to" an on-domain URL, are they gaining domain authority each time someone publishes a shortened link from their service? Or does Google penalize these sites specifically, or links that redirect in general? Or am I missing something else?

[RyanKent]

Jay, you are asking a great question and the answer is yes, links that are offered from URL shortener services build DA.

Think of those links as 301s. When you use http://bit.ly/xyz that URL is 301'd to the actual web address. As with all 301s, you do lose a bit of link juice due to the 301, but 90%+ of the value will remain.

[Jay.Neely]

Ryan, thanks for responding, but I may have not been clear in my question. Your answer is about domain authority for the ultimate destination of the link; let's say http://bit.ly/xyz redirects to http://www.seomoz.org/q/are-url-shorteners-building-domain-authority-everytime-someone-uses-a-link-from-their-service

And let's say 20 people on tweet the http://bit.ly/xyz link, and the text of several of those tweets is reproduced (link included) on eight websites. Does http://bit.ly 's domain authority increase as a result of those 20 tweets and eight website links?