title: What are some good Ruby-based web crawlers?
body: <p>I am looking at writing my own, but I am wondering if there are any good web crawlers out there which are written in Ruby.</p>
  
  <p>Short of a full-blown web crawler, any gems that might be helpful in building a web crawler would be useful. I know this part of the question is touched upon in a couple of places, but a list of gems applicable to building a web crawler would be a great resource as well.</p>