I'm a lead developer of WordPress. There are a lot of WordPress groups on
meetup.com (we're involved in the chapter account program) and we'd like to add support for
meetup.com's oEmbed endpoint in WordPress itself (the one documented at
http://www.meetup.com/meetup_api/docs/oembed/).
oEmbed is a fairly fragile and esoteric specification, and we've seen API providers ignore, break, or remove support for it, which can cause grief for users. Twitter.com, for example, has now broken it four or five times. :-) So before we add new providers, we try to double-check with them that their endpoint is actively supported.
Thanks!