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.
Capitalization rule #2. Use capitals for proper nouns. In other words, capitalize the names of people, specific places, and things. We don't capitalize the word bridge unless it starts a sentence, but we must capitalize Brooklyn Bridge because it is the name of a specific bridge.