signor_john - 1:38 am on Nov 20, 2009 (gmt 0)

I think there are at least two reasons why the Web breeds "serial entrepreneurs":

1) Web businesses can often (not always) be started cheaply and easily, so if Site X is successful, why not try to duplicate that success with a Site Y?

2) Web businesses are often built around fads, trends, search-engine vulnerabilities, technical advances, etc. Thin affiliates with disposable domains, made-for-AdSense scraper sites, user-generated content sites, and (more recently) long-tail cheap-content sites have enjoyed windows of opportunities at various times, but when those windows have closed, the owners have had to move on to the next big thing. This happens in the brick-and-mortar world, too (think of croissant shops giving way to bagel shops, or Vietnamese restaurants being replaced by Thai restaurants), but in the offline world, change--and the need to react to that change--tends to occur more slowly than it does online.