Edwin - 9:47 pm on Aug 20, 2010 (gmt 0)

A keyword based TLD isn't required to succeed, in fact the biggest and most successful sites online have more unique and brandable domain names.

Wrong conclusion, because the sample's biased. By starting from the most popular sites and working backwards to your conclusion, it's like taking the finalists in the Olympic 100m and concluding everyone can run a sub-10s race.

By picking only the winners in your example, you're glossing over the hundreds of thousands of smaller sites and all the sites that have tried and failed to gain traction. Also, most of the sites on your list have at least tens if not hundreds of millions of dollars in investment propping up their leader status.