A gallery of sites using sitty irritating modal popups. The creator of the site also has a blog post explaining the wheres and whys, in which he says:

What we’re witnessing here is the first wave of the second world pop-up war. Those of us who lived through the first one can only describe the horrors to our disbelieving children. This time though, the pop-ups are winning because we don’t yet have the tools to fight back. The web has seemingly evolved into something that actively antagonises people — why would anyone in their right mind hide the content that visitors are there to see?

There’s also a browser extension for easy, automated, Twitter-complaining to sites using these “technologies”.