I'm tied in with search keywords to scan for anything related to web conferencing, webinars, webcasts, podcasts, web seminars, and so on coming from the major wire carriers and Google. I see lots of press releases about investor calls and financial results webcasts (because corporations have to publicize those).
But I am astonished by the lack of press releases related to common marketing and product-related webinars. I know companies are producing these events, but they seem to be keeping notices just listed on their own websites! Very shortsighted. People coming to your website to check for events are a tiny self-selected portion of the general population that could benefit from your material. You need to reach out to that vast untapped audience.
A press release for this kind of event is not designed to elicit press coverage. It is there purely to get you listed and crawled by automated search engines. It can be nice and short, basically just the details of the date and time, a description of the subject matter, and most importantly -- a clickable link to the event information/registration page.
And while you're doing that, since you have all the information in one place already, why not list your event on WebEventSearch.com at the same time? It's free and provides yet another all-important incoming link to your registration page. The name of the game in Internet publicity is links and search prominence. Forgive my bluntness, but you're crazy if you don't take advantage of every easy opportunity to make your event visible to the Internet audience through search engine awareness.
Every time you create a new webinar, webcast, streaming feed, podcast, or web-based seminar series you should be issuing a small press release to Market Wire, Business Wire, PR Newswire, or some similar news carrier that is scanned by the search engines. Your audience is looking for you. Help them find you.