elance and ...who else ?

say ...I have a domain

that is www.worldwidewidgets_____________.com

and wanted to add different widgets in the 'blank'

how would that be done ? would it appear like

www.worldwidewidgetsbicycles.com
or

just be another page on the site ?

ok ...so I need a domain name that will do what I want but that method would not work..

how to people 'mask' the domain name...? all this hype abaout the LLLL.com and all makes me wonder if any domain name is really any good, if they can use one domain and have it look like another ...

know what I mean, Vern?

hope this is clear ....thanks