Use WhoIs lookup anytime you want to perform a search to see who owns a domain name, how many pages from a site are listed with Google or even search WhoIs address listings for a website's owner.
The word act, as used in the term Act of Congress, is a common, not a proper noun. The capitalization of the word act is deprecated by some dictionaries and usage authorities. Some writers, in particular the U.S. Code, capitalize Act.
Writing Tip: Is it Federal or federal? This question comes up rather frequently. For some reason, many people think the word federal always warrants a capital F. Actually, you should capitalize federal only when it is part of a proper noun, that is, the official name of a particular or unique person, place, or thing.