I didn't even suggest, let alone say, that google searches in realtime. Google maintains a massive database but the data has to be retrieved and while there are indeed a number of caches involved to speed things up this does not remove the need to get data from the db. Of course it retrieves more than the first 50 items - how else would I be able to read the whole thread.

As far as computing power is concerned I could run this site on the notebook I'm using right now and to load balance you need to double up on something: the webserver (sw), the db (sw) or the machine itself.

At the risk of repeating myself, I doubt if this is a cost issue except in terms of time (which of course can be a big problem). There are many, many sites - much larger than this one - running on totally free open source software.