I think the the results quality on Google has been the same or better over the last few months; one thing we have been looking at is helping less savvy users who might mistype a word or type extra words that they don't really need in their query. That can be a little more annoying for power users, but on the other hand the power users pick up tricks like "Use a '+' in front of a word to require Google to match that word."
Regarding the query [Linux asynchronous IO] returning older results, here's a tip. Above the search results click the "Show options" link to open up what we call "toolbelt" mode. From there, you can click to show only results from (say) the last year, or in a certain date range.
Toolbelt mode is really handy, e.g. if you search for a product, you can click "Show options" and then click the "Fewer shopping sites" link to get more reviews and manufacturer pages instead of comparison shopping sites.
Regarding the query [Linux asynchronous IO] returning older results, here's a tip. Above the search results click the "Show options" link to open up what we call "toolbelt" mode. From there, you can click to show only results from (say) the last year, or in a certain date range.
Toolbelt mode is really handy, e.g. if you search for a product, you can click "Show options" and then click the "Fewer shopping sites" link to get more reviews and manufacturer pages instead of comparison shopping sites.