In this paper, we are describing Forum Crawler Under Supervision (FoCUS), a supervised web-scale forum crawler. The goal of FoCUS is to crawl relevant forum content from the web with minimal verhead. Forum threads contains the information about the target of forum crawlers. And the forums had several styles and they are powered by different forum software packages. They always have similar implicit navigation paths connected by specific URL types to lead users from entry pages to thread pages. Based on this observation, we reduce the web forum crawling problem to a URL-type recognition problem by the following techniques and methods.