Just some anecdotal evidence.

We released a site some three years ago. It sat on our oldest server for the first 18 months, and it didn’t do so well in the search engines. Did around 8000 pageviews a day, with revenue at a partly $25-35 a day. Nothing impressive.

Then when we finally got our new server configuration up a while ago, we moved it. Instantly traffic went up a little bit - the site was faster, the search was faster, etc etc. Google also went crazy, crawling a *lot* heavier, and also sending more traffic.

Yesterday the site did 22,000+ pageviews, and over $170 in revenue (admittedly a little bit high, usually with that many pageviews it does roughly $125 on average).

Just as interesting is that (now) three of the top five (and the top two) are searches for the brand itself. That was not the case when it was on the older server.