Google's Index Doubles, But...

... I am not sure how it will affect me as an end-user. Google's index is now over 8 billion pages. How did they do it? In the past, the index has grown by adding many different filetypes. The set of filetypes does not seem to have grown this time.

Bill Coughran writes-

Comprehensiveness is not the only important factor in evaluating a search engine, but it's invaluable for queries that only return a few results. For example, now when I search for friends who previously generated only a handful of results, I see double that number. These are not just copies of the same pages, but truly diverse results that give more information. The same is true for obscure topics, where you're now significantly more likely to find relevant and diverse information about the subjects. You may also notice that the result counts for broader queries (with thousands or millions of results) have gone up substantially. However, as with any search engine, these are estimates, and the real benefit lies with the queries that generate fewer results.

I am not sure that makes a difference for me. Most searches I run lead to more than "a handful of results". So, here's the question. Does the size of a search engine's index after a point?