EventSpan just published an API for developers who want to grab content listings from the site. That may sound dry and uninteresting, but it's actually a fascinating wrinkle on the straightforward event search functionality most others in this space have concentrated on providing.
Instead of requiring visitors to come to the website and manually enter a search term to find events of interest (which is still possible), other web programmers and application developers can programmatically make calls to the database of listings and work with the results to display them in other places. This is part of the syndication model that EventSpan mentions in its self-description.
By making it possible to spread event listings out to multiple access channels, EventSpan can potentially be more attractive as a repository site for people choosing where to list their events. On a classic event search site, the only people who will ever see your event listing are those who go to the search site. But EventSpan has now opened the door to having your event show up on other engines. I don't know why the major search engine vendors wouldn't jump on this opportunity and pull the listings for display on their sites.
Consider Google. There are now special Google search specialties for blogs, books, groups, patents, photos, and shopping sites. If they can grab a source for events, why not add that to their list of offerings? It's an interesting thought and one might wonder whether EventSpan is killing itself by empowering competitors. But then all one has to do is think back to the early days of personal computing. The PC opened its architecture and allowed others to work with their specs. The Apple didn't. Market share over the years reflected which of those was the more successful strategy from a revenues perspective (I'll leave debates about quality preferences out of this!).
I notice that EventSpan has not published a similar automated standard for uploading events onto the site. You have to contact them if you are a bulk listings provider. Probably a good idea there... All kinds of garbage could come flooding in otherwise.
This is worth keeping an eye on.