>>For example, a standard spellchecker will probably pull us up still if we typed "I hoovered the carpet", seeking to make it a capitalised noun. Yet I doubt if anyone thinks of it as only a brand name by now.<<

I do. Apart from when I read messages like yours and when I watch british television, I always think of hoover as only a brand name. I have never used hoover as a verb before, and neither has anyone I know.

"A sobering thought: what if, at this very moment, I am living up to my full potential?" JANE WAGNER