Recently the St. Louis Art Museum unveiled a new web site - with a new domain name!
What was once slam.org is now stlouis.art.museum (or saintlouis.art.museum - both work). And slam.org just redirects to the new address.
In 2001, the Museum Domain Management Association was empowered to manage the dot-museum top-level domain, approved by the Internet Corporation For Assigned Names and Numbers (ICANN) in 2000. This was one of three new "sponsored" top-level domains (TLDs) approved at that time and "designed for use within a specified community. Registration restrictions for these TLDs have been developed by the sponsor with input from the community." Thus dot-museum, although controversial at its initiation, is intended as a global standard for all kinds of museums.
The other two sponsored TLDs were arguably even narrower: dot-aero, specifically for the aviation business; and dot-coop, for cooperatives. For example, West County-based Missouri Corporate Credit Union, which is (believe it or not) a credit union serving other credit unions, uses the dot-coop domain.
These three rather obscure TLDs were created at the same time as a variety of somewhat better-known "new" TLDs: dot-biz, dot-info, dot-name, and dot-pro.
There is another, much older option for museums located in the U.S., but most have not used it: the "locality" version of the dot-us TLD. You know, the ones like state.mo.us, slps.k12.mo.us, slpl.lib.mo.us, co.st-louis.mo.us and ci.st-louis.mo.us. The art museum would have been something like slam.mus.mo.us - not exactly easy-to-remember.
Of course, somehow dot-com has become what everybody remembers. Even so, there's always been dot-net, dot-org (which many of the former dot-us entities, particularly K-12 school districts and public libraries, like SLPS and SLPL have recently moved to), dot-gov (owned by the Feds but which has allowed some state and local entities like the State of Missouri and the City of New York to move in to their space), and dot-edu (now open to community colleges, shifting many of them, including StLCC, off the dot-us namespace).
Then there's dot-mil. I don't think anybody else wants into that one. Indeed, civilian Department of Defense jobs are posted on a dot-org, and military recruiting is usually done on dot-coms.