Why link shorteners hurt the user experience and destroy the Web?

Selected answers from the Dumb SEO Questions Facebook & G+ community.

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  Sudhir Mantena: Came across this strong argument against usage of link shortners. Seems convincing but have a question. Hope someone here could answer that.
  - Bitly custom shortener does a 301 instead of 302.
  
  I do see that all the likes, +1s for the short link now pass to the long URL. But does it also pass the entire seo value as well? 
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  Bret Carmichael: I'm unaware of any SEO problem with URL shorteners. The true problem is link rot. "Personalized" shorteners spring-up and disappear all the time. When they disappear, all the links are made dead: rotten. Google, Twitter, Facebook, etc. all use shorteners. 
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  Edwin Jonk: From the expert panel in this weeks SEO Questions hangout on air on 00:02:43 into the YouTube video: https://dumbseoquestions.com/q/why_link_shorteners_hurt_the_user_experience_and_destroy_the_web +Sudhir Mantena
  
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