If you know of any to add please let me know at email@example.com
An example of this is what almost happened to Kleenex.
For example, I think a trade name can fall into the public domain if it becomes the descriptive name for an item. In other words, it can be *too* successful. This almost happened to "Kleenex." Velcro didn't fall into the public domain because its owners were careful to keep "hook-and-loop" around. I can't think of a case (with case law) where it did happen, but it is certainly a real possibility. Perhaps there is an intellectual-property analogue, or perhaps there could be an implication that a copyright infringement was permitted if not objected to under certain circumstances. As we all know, the Internet does pose some new legal issues. (From a Usenet Article by Amarna, firstname.lastname@example.org)
However, Viacom denies this in a recent news article,but others think otherwise:
Glouberman [a Toronto-based Web publisher who runs a page devoted to trademark wars on the Internet] suggested that part of the impetus behind Viacom's letter was simply that it was posting its own official Star Trek site, Continuum, as part of Microsoft's network. Viacom executives deny this.
But Mike Brown, who runs an official Star Trek homepage (www.cdsnet.net/vidiot) and has communicated with other Trek fans, site-operators and Viacom executives, said "the timing is a little coincidental."