When I first starting reading about I thought it was probably bunk - not anymore.

There has been some speculation that the major changes in Google that are happening with this current update are due to Google beginning to use Latent Semantic Indexing - which is basically a method used by search engines to learn to associate certain terms with concepts.

It used to be (forever and ever) that if you searched for "anycity relocations" the results would show mostly real estate sites. Now it will show mostly moving sites - Google now associates relocations with moving and not with buying real estate. All the conventional SEO in the world to get a real estate site to come up for relocations searches probably no longer work.

Very interesting development if you ask me!

There is more about LSI in this thread.

Here is an interesting google query.

~real estate -Estate -Realtor -Real Estate -home -property

I don't know what Google was showing for results when you tried it but it shows no results now. In order to get anything at all I had to cut it down to ~real estate -estate -Realtor which gave some pretty silly results. So does just searching for ~real estate.

I find it hard to believe that Google thinks the sites presented have anything in common with real estate. Winzip? Seti? Nasa? No wonder folks are complaining about Google's index.

The query I posted above supposedly shows the words which google thinks are related to "real estate". The ~ operator is supposed to show results that are related to the phrase you're searching for. You'll see that a search for "~car" brings up BMW, because well, people think of cars when they think of BMW (the same way people think of BMW when they think of cars).

So if you take a query like "~realtor", filter through the bold words in the top ten results (e.g. -realtor -realty [those are the two bolded words in the top ten]) you will find that the two things that google things are related to "realtor" are "realtor" and "realty"