"There's another about a pair of Googlers, each married to other people, secretly having a child together."
How is this possible? Are they adopting? It seems like if one of them is a woman and she is bringing the child to term, her husband would notice. Unless she just doesn't see him for ~5 months (which I suppose is another possibility)
I'd choose Ruby in a service oriented architecture. Use HTTP/JSON for internal APIs between distinct systems. If performance becomes a business-limiting factor, you can investigate replacing a single part of the system with a lower-level language (Java, Haskell, Go, Erlang, etc).
Rails (and in particular the RailsApi gem) makes prototyping and putting together a SOA like this easy and fast. Except for the API client, which I don't yet have a good solution (ie, what ActiveResource was supposed to solve).
I disagree that the slow part of a RoR app is the database - from my anecdotal experience, the slowest part is rendering views and the string manipulation there-in, probalby caused by GC. For a Rails 2.3 App with REE and MySQL, time is ~25% GC, ~25% DB and 50% ruby (from NewRelic).
However, premature optimization and all that, don't choose Java because its faster than Ruby in some arbitrary benchmark. Choose Ruby because it makes you happy and you can meet business objectives faster and easier with it.
For a site put together by search engines, the URL structure for the site search is atrocious. "#q=Product" and not "?q=Product"? Who thought that was a good idea?
Site also looks a bit like spam. Needs more Firefox-esk awesome graphics, imo.