71% of sites are detected with a known language/framework/technology. Among them, here's a rough breakdown.
72% sites has some sort of visitor tracking tech.
57% of sites have ads.
3% has blogs.
4% uses CMS.
2% sites has ecommerce.
22% has feeds.
4% sites has media.
16% uses CDN. It is used for example to auto find the nearest server to distribute video.
30% sites has widgets.
70% declared a encoding, of which, 60% uses utf-8, 40% uses iso/iec-8859.
Info of this page is from trends.builtwith.com. Another useful site is backendbattles.com