Common URL Extensions

.edu Educational organization (most US universities)
.k12 US school site (not all US schools use this)
.ac Academic institution (outside of US)
.sch School site (some schools outside of the US use this)
.com Company (usually .co in the UK)
.org Any organization
.gov Government agency
.net Network
.mil Military institution
.biz Commercial purpose / business
.info Commercial purpose / business
.uk United Kingdom (country specific extension)
.jp Japan (country specific extension)
.ca Canada (country specific extension)
.au Australia (country specific extension)

(~)        Sometimes you might see a “user” reference or tilde (~) symbol in a sub directory, followed by a name. This indicates that you may be on a personal Web page that is being hosted by an ISP (Internet Service Provider).