I recall, when living in Minneapolis (1997-2003), there was a trademark fight between Amazon.com and a local bookstore called Amazon. I don't recall how it turned out.
By the way, a bulletin board inside the Lost Dog Coffee store has some cute sayings, like "Compassion is revolution" and "Politicians and babies both need to change diapers".
Should "common words" be available for new national trademarks under these circumstances? Can common words become a legitimate source of brand identity for a previously local business?
In the gay community, bars have sometimes used workmarks for national identity, like "JR's", which started in Dallas and spread to many cities. But other names (like "Saloon") have tended to remain just local.