Can someone explain why we want to crawl and/or monitor? What is this used for?<p>When I think of a crawler, I think of a non-homogonous network (if that is the right term).<p>But with the blockchain, isn't it the case that each node has an entire copy of the blockchain, so you don't need to "crawl" it, it works more like a database.<p>What am I not understanding about this?