XSS attacks were becoming more popular because more and more websites were writing their own snippets of code so visitors could get more out of a site, he said.
BBC NEWS | Technology | Hackers exploit poor website code
Here's the downside the Web 2.0 – a lot of what web designers are trying to accomplish has never been done in quite the same way before. That means that they're writing a lot of custom code… and making a lot of the security mistakes that 'standard' code had eliminated years ago.
So… 'bout time we found a serious downside to Web 2.0.