What’s next for Spotify? That’s the question posed in an invitation that was sent out today for an event slated for next Wednesday. It mentions “a new direction for the company,” but details are thin beyond that. While it may be a longshot, what if a Spotify music store is on its way? This may not be quite the grand slam decision that you may think it is.A Spotify Store doesn’t make a lot of sense. If you’re a paid subscriber, why would you want to buy music? The point of joining services like Spotify, Rdio, and Grooveshark in the first place is that you don’t have to bother with that any more. If you’re forking over $10 per month for all-you-can-eat streaming, you don’t want to buy additional songs or albums — especially when you could almost as easily get them from iTunes, Amazon MP3, or Google Music and import them to Spotify.This Spotify Music Store would be dangerous ground to walk. We already see popular songs often withheld from the streaming library, despite the rest of the album being available (see right). Making it that easy to buy missing tracks could lead to more labels and artists engaging in this practice. A Spotify Store could lead to a streaming library that has thousands of filler tracks you probably don’t want, with the best stuff requiring a series of 99¢ purchases.The frightening thing about this is that Spotify and the record labels would probably make more money with this model. Any MP3 sales are more than they’re getting now, and — now that the service has grown in popularity — they could probably add something like this without facing too big of a mass exodus. It may lead to a more watered-down, fragmented streaming library for users, but it could mean bigger profits for Spotify and the record labels.Fortunately, services like Spotify aren’t just competing against Rdio, Rhapsody, iTunes, and Amazon MP3. They are also competing against an impossible opponent — The Pirate Bay. Many of Spotify’s customers are undoubtedly former pirates who are contributing money to the music industry for the first time in their lives. They do this not due to a moral awakening, but because it’s more convenient to pay Spotify $10 a month than it is to hunt down, upload, and sync a bunch of files. If Spotify gets too clever, many of their users would rather go back to their old ways than fall for a bait-and-switch.We may not need to worry about any of this though, as there are a million other things that Spotify could be announcing next week. They could be expanding their social features, issuing Google Music-like “letting your friends listen once” functionality, or offering some other unforeseen new implementation. Heck, they could even just be adding an iPad app.If the event does, however, have Spotify pulling back the curtain on a music store, let’s hope that the company is aware of the potential pitfalls that could lie down that road. It might end up hurting them just as much as it does their current customers.