User blog comment:BlitzerRyuusei/Rating supports by their poke, sustain, and burst/@comment-6399518-20131010171314/@comment-5556439-20131011173414

Supports job isnt to help the AD Carry early on. Its to provide SUPPORT to the team. They are only placed with a Carry (doesnt have to be AD) to negate their early weaknesses and allow them to freely farm, and control their lane without the threats of playing vs someone who can stomp them like Irelia or Jax.

After bot, it depends entirely on the supports playstyle and kit whether or not they pay even the slightest amount of attention to the teams Carry's. In many cases, playmakers like Thresh, Blitz, and Alistar are better off roaming around to other lanes or the jungle to help out the rest of their team after bottom can take care of itself.