Crawling sucks.
I wrote my first crawler in a few lines of perl code to spider a website recursively about 10 years ago. Two years ago I wrote another crawler in a few thousand lines using java+php and mysql. But this time I wasn't really interested in competing with google, and instead crawled feeds (rss/atom). Google hadn't released its blog search engine at that time. Using the little java knowledge I had and 3rd part packages like Rome and some HML parsers I hacked up my first crawler in a matter of days. The original website allowed users to train the bayesian based engine to teach it what kind of news items you like to read and automatically track millions of feeds to find the best content for you. After a few weeks of running that site, I started having renewed appreciation for the search engineers who breath this stuff day in and day out. That site eventually went down... mostly due to design flaws I made early which I'm listing here for those who love learning. Seeding proble