Top 20 Websites in US

Web metrics firm Compete has an interesting post, outlining the top 20 websites (for US traffic). According to Compete, all 20 of them got over 20 million unique visitors in October 2006. Here is the chart:

A couple of people noted in the comments that if you add Microsoft's 4 top 20 properties together (msn.com, live.com,microsoft.com and passport.net), then they would probably be number 1. However a counter to that is that a lot of passport.net domains currently re-direct to live.com. I think there may be some crossover between live.com and MSN too. So it may well be that Yahoo remains number 1, even accounting for Microsoft's multiple brands. Plus of course Yahoo and Google both have separately branded properties too - e.g. Flickr, YouTube. If I was to estimate, I'd put Microsoft at number 2 overall - but interested to hear what others think.

Compete notes that Adobe.com, Live.com, Wikipedia.org and YouTube.com are new to the top 20 over the past year,while Expedia.com, Monster.com, Paypal.com and Weather.com have all dropped out.

Looking at the Alexa data for US traffic, the top 20 is quite different:

1. yahoo.com
2. google.com
3. myspace.com
4. msn.com
5. ebay.com
6. amazon.com
7. youtube.com
8. craigslist.org
9. wikipedia.org
10. cnn.com
11. facebook.com
12. go.com
13. live.com
14. blogger.com
15. aol.com
16. microsoft.com
17. comcast.net
18. imdb.com
19. digg.com
20. flickr.com

The Alexa list is (I think) only counting US traffic, but it is quite different from Compete's stats. The presence of non-mainstream web 2.0 sites in Alexa's top 20 (blogger.com, digg, flickr) suggests that the traffic is heavily skewed towards technical users - which makes sense, given Alexa relies on toolbar downloads to get their stats.

Also interesting to note there is just one Microsoft property in the top 10 in Alexa, compared to 3 for Compete.

Various web browsers

Browser	Release date	Platform	Rendering engine	Standards support
Microsoft Internet Explorer 6	2001	Windows, Linux, Unix	Trident IV	CSS 1, some CSS 2, some CSS 3, ECMAScript, DOM (with proprietary implementations and quirks)
Microsoft Internet Explorer 5 and 5.5 (Windows)	1999 (5), 2001 (5.5)	Windows, Linux, Unix	Trident II (5) and III (5.5)	Most CSS 1, some CSS 2 (with bugs), partial support of ECMAScript/DOM
Microsoft Internet Explorer 5 (Macintosh)	2000	Macintosh	Tasman	CSS 1, some CSS 2, some CSS 3, ECMAScript, DOM (buggy and not complete)
Netscape Navigator 7	2002	Windows, Macintosh, Linux, Unix	Gecko	CSS 1, most CSS 2, ECMAScript, DOM
Netscape Navigator 4	1997	Windows, Linux, Macintosh, Unix	N/A	Some basic CSS 1, JavaScript, no DOM because it was written after NN4's release
Firefox 1.0	2005 (pre 1.0 release versions available in 2004)	Windows, Linux, Macintosh, Unix	Gecko	CSS 1, most CSS 2, some CSS 3, ECMAScript, DOM
Opera 8.5	2005	Windows, Linux, Macintosh, Unix	Presto	CSS 1, most CSS 2, ECMAScript, DOM (Opera 7 was the first version with DOM support)
Safari	2002	Macintosh OS X	KHTML	most CSS 1, some CSS 2, some CSS 3, ECMAScript, DOM (with bugs)
America Online	Various	Windows (there is a Mac version, but it isn't as well supported)	Trident	CSS 1, some CSS 2, ECMAScript, DOM (same as Internet Explorer, but expect additional buggy behavior)
Lynx	1993	Unix, Windows, Macintosh	N/A	N/A

Rendering Engines

A rendering engine, also known as a layout engine, is the code that tells the browser how to display web content and available style information in the browser window. The rendering engine is responsible for the size of an unstyled h1 heading or how a horizontal rule looks on the page. It's also the key to the correct implementation of CSS and other web standards.

The first separate and reusable rendering engine was Gecko , released by the Mozilla developers in 1998. It was notable for its small size and excellent support for standards. Now web developers pay attention to underlying rendering engines as a key to understanding a browser's performance.

The Wikipedia, an online collaborative encyclopedia, has a detailed comparison of rendering engines, where they are used, and what they support at http://en.wikipedia.org/wiki/Comparison_of_layout_engines.