Existing Business Name and Slogan...

[rcristel]

Lets say I own the MLSSouthDakota.com domain and wanted a slogan for the site.

If "Multiple Listing Service of South Dakota Inc." is already a company, what are my limitations for a slogan?

Could I use a variation of their company name?
e.g.. South Dakota Multiple Listings Services

Also, could the owner of "Multiple Listing Service of South Dakota Inc." take legal action to take ownership of MLSSouthDakota.com?

Thanks