The top beer websites are based on the Alexa website rankings that are released weekly/monthly and quarterly. I look at the quarterly stats when reviewing these types of websites as it gives you growth over 3 months. I recently ran a Top 30 List for 2012 beer websites.
It is no surprise that the large beer companies have high ranking websites due to the sheer volume and size, where as smaller websites that are likely run from basements or spare rooms of the creators are the ones that are biggest surprise. In terms of country usage we can see the US, Europe and Japan all share the top ranking websites.
As a beer lover I use all sorts of major websites for beer information and use blogs to read about what other beer lovers enjoy about beer festivals, bars or beer trends. Beer Trends is what I enjoy reading about and to my suprise it was a previous post of mine from BlogCritics that comes up #1 in Google rankings for 'Craft Beer Trends'.
1. 
Beer Advocate is a beer Website that is the global leader in Beer Information, Contains Reviews and Beer Communities. Setup by Jason and Todd Alstrom, based in Massachussets US. Primarily a US based audience but with Global Beer information.
2 
Home Brew Forums a Beer Website is for homebrewers to share and discuss beer recipes and forums. This has a high return usage by members for the community of beer lovers who brew beer.
3. 
RateBeer.com is a site that is the competitor to Beer Advocate in terms of beer information. Though I view them as complimentary in terms of beer knowledge and data. They release 'TOP 50 lists' every year and provides great data insights for beer lovers like myself. I recently reviewed the 2009-2011 Top 50 lists released by RateBeer.
4. 
Kirin is a Japanese brewery and the primary audience is in the Japanese market with 99.8% of audience based in Japan. Kirin is a subsiduary of Mitsubishi Motors that make cars, fridges and a range of other appliances. 23% of all Kirin Beer produced is exported abroad.
Article comments
1 - Dr. Joseph S. Maresca
Looks like great beer from here!
2 - Beer Collectibles Jimmy
My favourite site is still Beer Classifieds. Lots of cool stuff on that site... nostalgia for the past... all kinds of other stuff.
That said, Ber Advocate is chock full of beer-obsessed people.
3 - James
How is Saveonbrew.com not in your top 10 beer websites. They advertise the cheapest advertised beer nation wide and also have blogs and beer information. Might want to check them out.