claus - 5:25 pm on Apr 4, 2005 (gmt 0)

>> But for what % of search terms?

I did not mean search terms. For 100% of anchor text terms. It could run.. well, i don't know... perhaps every time any page was indexed: If link found, then add anchor text + URL to the table.

If you then wanted to do something at search time, then it will be a simple lookup in a table, no expensive calculation needed.

>> 8 billion documents

I personally suspect that at least 10% of those are not documents as such. Still, even for the part that are real documents - it's a lot of documents. But then again, Google has got a whole lot of capacity, and they increase it continually.