99% of Google's reported revenue comes from search (or rather advertising programs) according to their 2008 company report (I know a little outdated, the number is probably a bit different now but I can't be bothered to look it up, I'd guess still pretty north of 90%).
Doing some quick arithmetic gives me about $200 million left over from all other products and services combined.
Google Apps for business accounts for around $100 million of that (2 million users * $50/yr), which means that really, all other products in Google make up around $100 million dollars/year. I'm willing to wager that a very significant chunk of that remaining $100mil comes from Google Earth geospatial servers for the military and the rest going to the appliances (which surprisingly are not the big hit everybody thought they would be, the appliances should be a multi-billion/yr business unit alone, what went wrong?).
Now, $200+ million is nothing to sneeze at, but we wouldn't talk about Google with such hushed, excited, reverence if they were a $100 or $200 million/yr company, would we? Salesforce.com, which basically sells one thing, just did a Billion dollar year. We also have no idea if those figures represent profit or not. Google docs for example runs on the same multi-billion dollar infrastructure as does search...would it be nearly as compelling of a service if it really had to pay for itself?
We all conflate their great technology with their market success, but really Google is just a really good advertising conduit that just so happens to have really good technology -- their other technology is not impactful in nearly the same way monetarily to them.
By way of comparison, Google is about the same revenue-size as the top-5 advertising agencies.
But Google's actual technology business is about the size of ClickSoftware Technologies(NASDAQ:CKSW) -- and I don't recall seeing lots of posts on any tech site about their offerings.
None of this is any great mystery. The numbers are out there and it's easy to make some educated guesses. Google knows this too, which is why they are rapidly trying to diversify into other areas. For example, Google Docs was a $0/yr business not that long ago -- I wish I could turn a switch and grow something into a $100mil/yr operation in a couple of years.
On the other hand, if we look at Microsoft, they aren't even interested in an idea unless it has at least a billion/yr revenue opportunity attached to it. So many of the things that Google is doing now, to build up to, and exceed, that kind of revenue target, would never have happened at Microsoft -- and there's something to be said about that.