hotsh/rstat.us — comment on commit 0486e6c5a42bf63304473f4749a57746fcbb0ccb
File: app/models/update.rb line 270
By steveklabnik:

The purpose was to never post the same text twice, like Twitter. I think double clicks happend, too. @wilkie do you remember the exact scenario when we added this? I don't think we did at first, and then something happened.