Tumblr wins because it's twice as fast
blog.yottaa.com
blog.yottaa.com
The bald assertion that Tumblr is more successful than Posterous because it is faster is repeated about a half dozen times during the piece but no evidence is ever advanced to prove this point.
Without further data, at best, we're talking a correlation. I could similarly argue that dropping the 'e' in Tumblr is a 'big reason' Tumblr is more successful than Posterous (which, please note, contains an 'e'!).
The article does not pinpoint the success or failure of a business into a single reason. The article didn't claim "performance is The reason" that Tumblr is successful. It says "performance is most likely one of the key factors".
Towards the end of the article
>> Suprising Results
40-60% of Yahoo!’s users have an empty cache experience and ~20% of all page views are done with an empty cache. To my knowledge, there’s no other research that shows this kind of information...
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