title: What is a signal in Django
body: <p>I come from a java background, but I'm working on a django-based website. To that end, every now and again I search for something, and I keep on seeing references to "signals". I'm unsure if this is a django thing, a python thing, or some sort of other thing that I never bothered about before.</p>
  
  <p>Can anybody enlighten me what a "signal" is? </p>
  
  <p>cheers.</p>
  
  <p>UPDATE i have zero idea about signals. I know, I know, this is probably a <em>big</em> question... but you know how when you read about something, and you don't know what it is - that unknown unknown kinda thing? From the comments.... a signal is from the os?</p>