I have created a movies blog 2 year ago and I get 1000 visits per day. Another person have created a similar blog a few months later but it get at least 100.000 visits per day. It has only PR 2 but alexa of 2000 ( this is the blog of the my competitor: tinyurl com/6jwrzfj ). Is there a way to know what are the main sources of traffic for a website ?
I would use a tracking application, like Google Analytics, to track the traffic to and on your website. Probably the competitor is better ranked in the search engines, better keywords or has links in some places that get many visitors interested in his site.
Search engine keyword targeting and quality backlinks on relevant websites. Word of mouth via social networking is also big.