KRM Information Services posted a short podcast last November in which they interviewed Tony Bourget (their corporate research attorney) about the legal protection accorded the coined term "webinar." It's a fun but occasionally frustrating listen.
As with most issues in the confusing world of patent and trademark protection, the expert was unable to offer much in the way of absolute answers to the interviewer's questions (it might just be me projecting, but I felt like the poor interviewer was getting more and more exasperated as the interview went on and he couldn't get a simple yes or no to anything out of his subject expert!).
Tony pointed out some interesting facts about the legal status of "webinar." An individual did indeed register the mark back in 1990 (Wait a minute... That seems way too early. I just looked up the registration and it says the filing date was 1998, which is more reasonable, especially since the official registration grant is in 2000) -- but only as a design/style trademark registration. That means the specific printed depiction of the word in its unique format is protected, as you would a logo. In this case, apparently the first three letters are capitalized. The unnamed registrant assigned the ownership of the mark to InterCall and I have to tell you that I was unsuccessful in finding any mention or depiction of it on their website.
You would think that lets everybody else off the hook, but there is a clause in trademark law that protects a registered mark from a competing mark that could be construed as misleading or confusing with the protected mark. What constitutes "confusing" is completely up to the courts however, so an attorney can't give you any absolutes on whether you are safe or not. The economics of legal practice argue in favor of fuzzily worded statutes that require paid services to settle (Oops... Is my bias showing?)
It turns out that we are right at the end of any grace period for the owner of the trademark registration to refile ownership and show use. I rather doubt that InterCall would bother at this point. As Tony points out, there is such widespread use of the word (without any precedent of challenge) that it would probably be easy to label it as public domain.
In fact the word "webinar" has been (over)used to the point where it made it onto the annual Lake Superior State University List of Banished Words in 2005. It is in the esteemed company of such stalwarts as "blog" and "wardrobe malfunction." I wouldn't try prosecuting ownership of any of these.
Strangely though, Tony makes reference to someone who filed in August of 2006 for registration of "webinar" as a general word mark without regard to font or style in conjunction with a variety of web conferencing services. Although my company is Webinar Success and I use the term in my logo, I didn't bother to try for ownership, so don't look at me!
KRM talked about revisiting this subject in mid January and I hope they do. If so, you now have the background on the basic facts. Now get out there and advertise more webinars! Don't forget to use WebEventSearch.com. It's still free and still a great way to let people find your online events.