Some extra search capabilities of google include searching by top level domains. Google Site searching by TLD.
Some obvious benefits of this are narrowing down searches and weeding out junk sites. There are some even better search features are not too well known. One of my favorites is the the site search feature.
In a simple google search, append site:URL to the search. An example search for aikido on my site only:
Some additional features can be found here. I would like to see google incorporate multiple site searches in their feature set…