What’s next for Spotify: The ultimate rumor guide

The rumor mill is on high gear ahead of this week’s mystery Spotify event. Spotify has invited journalists to New York on Wednesday to reveal “what’s next” for the service, and only revealed that the announcement will be made by its CEO Daniel Eks and “special guests.” Ohh, the tease! Here are some of the rumors that have popped up all over the web in recent days, complete with out take on it:

Spotify will offer music downloads to complement its streaming service. Some have mused that Spotify could launch an MP3 store to compete with iTunes, (s AAPL) Amazon (s AMZN) and Google (s GOOG) Music. It’s certainly possible, especially since Spotify is already offering similar MP3 sales in various European countries. Then again, why would the company host what it calls a “global press conference,” just to extend a feature to the U.S. market?

Spotify will open up its API to commercial developers. That’s an intriguing theory, which has been favored by both Eliot van Buskirk and Peter Kafka. It goes like this: Apps that are built on Spotify’s API can’t currently be monetized. The company could change this, making it possible for any third-party developer to tap into Spotify’s music catalog to power their iOS apps or integrate music into their sites. The downside would be that any of these mashups would likely be restricted to Spotify’s paying users, but still – bringing Spotify music everywhere through an API that can be monetized would be an interesting next step.

Spotify will release an iPad app. Yes, it is overdue, and yes, it could be part of the package tomorrow. Maybe even a one more thing. But all that hubbub for an app release? Come on!

Spotify will launch a movie service. There have been rumors for a long time that Spotify was going to expand to offer video as well, but Ek has vehemently denied similar reports in the past. Of course, launching a video venture on the heels of a music service wouldn’t be completely without precedence: GigaOM broke the story last month that Skype co-founder Janus Friis is working on a Netflix competitor called Vdio, which follows his involvement in the music subscription service Rdio. Still, this one seems highly unlikely.

Spotify will launch a web player. This has been my own pet theory, and I think it still makes sense, possibly even in conjunction with a commercial API. After all, taking Spotify everywhere wouldn’t be half as spectacular if all third-party developers could do was to trigger plays within the app, or direct people to splash pages that ask them to install it. No, the real holy grail would be to actually play Spotify music within third-party apps and sites, with no additional software downloads required.