I had bought a domain name, hooked it up to my hosting, and started working on it. Mid-way through I decided to check to see if my site was indexed on google. I wasn't expecting it to be, because I didn't have any links to it or put it into any sites that would link to it (ei SEO Tools like Alexa). Sure enough, my website had been indexed. How did Google find out about my site? Does it just crawl any new domain that is purchased?