I'm surprised. I was using Scrapebox with a private proxy. I was scraping some keywords and harvesting URLs with just one connection. After removing duplicates and doing a do-follow check, I was left with 16 URLs. Did a PR check which took about 2 seconds. After that I tried to scrape for another keyword, but got a 302 IP block.. Now the question is, what had caused this? I was being very gentle with the private proxy, always harvested no more than 100 results, connections always set to 1, but still the Google banhammer struck me. Any ideas from you guys?