Definition of signal-boost in US English:

signal-boost

verb

[with object]
  • Share (another person's post or other online content) with one's own followers or friends on social media so as to raise awareness of an issue, event, etc.

    ‘we've been getting the word out, signal-boosting their petition, and generally making ourselves useful’
    no object ‘please signal-boost —tell your friends, their friends, anyone’

noun

  • An act or instance of signal boosting.

    ‘Laura got a huge signal boost when the singer/songwriter herself reblogged the video to her own platform’
    ‘please help us spread the word by giving the project a signal boost’