For Twitter, however, arguably the most important event of 2009 was not these publicity bonanzas but the introduction of the retweet button... As with Facebook,

For Twitter, however, arguably the most important event of 2009 was not these publicity bonanzas but the introduction of the retweet button... As with Facebook, the larger that Twitter’s social graph grew, the more attractive the network became. Pretenders to the short-message throne, such as Parler or Gab, struggled to get traction, as their networks lacked sufficient size and numbers of influential users to compete in a battle for attention. By 2011, Twitter, following in Facebook’s footsteps, passed the milestone of a hundred million users. While discussing the time period from 2009-2011, the article claims thats Gab and Parler "struggled to gain traction", but those services didn't launch until 2017 and 2018.