I filed my taxes this week. As always, I have to include all music-related income. Here are my lifetime earnings from Spotify:

$2.58! Those numbers are lousy, but I'm not really bothered by this. I've only been on Spotify since 2010, I don't really promote it at all, and I'm still of the mindset that up-and-coming artists should choose ubiquity over cash. We need to be in these popular music services -- otherwise we're just hiding in plain sight. Make your money elsewhere.

Low payouts aren't what's bothering me about Spotify these days. This week Spotify rolled out its new Play Button, which enables people to embed Spotify-powered music widgets on websites. Now, there's nothing inherently evil or wrong about this, and I'd argue that it's an advantage Spotify sorely needed. Even the biggest chest-thumpiest gorillas of the digital music space, iTunes and Amazon, don't allow you to create an embeddable widget that plays whole songs and albums.

The catch: for the Play Button to work, the user must have Spotify installed. Fair enough, gotta get paid somehow. Users without Spotify are asked to create a free account. And to create a free Spotify account, you have to have a Facebook account. This is where I start feeling itchy.

Last week, Facebook famously purchased Instagram, the super-popular photo-sharing app for a kersnillion dollars. A lot has been written about the purchase and what it all means, but I don't think its reaching to think Instagram could become the photo sharing experience on Facebook.

Meanwhile, what's the Facebook music experience? Trick question: there isn't any. Facebook doesn't have a built-in way to share or listen to music.

When you consider that, Spotify's Play Button starts to look an awful lot like Facebook's web-wide Like Button rollout of a few years ago. Facebook understood that sharing -- photos, music, YouTube clips, articles, blog posts, thoughts, ideas, whatever -- was a key activity of ordinary-person usage of the the web. So they rolled their Like Button out to the entire web, making it easy to share cool, you-gotta-see-this content into Facebook's data-gobbling doom vortex. To join in the fun, you needed a Facebook account, of course.

The heated debate over Facebook's intentions with Instagram has reawakened the larger conversation over Facebook's overall business of providing a shiny funhouse that hoovers up your habits and profile data while you play and spits it back at you as advertisements. Some have compared Facebook to a "company town," and while others have taken issue with this characterization, it doesn't seem too off the mark. Working in the chocolate mines might sound great -- and hey, free chocolate! -- but you're still a miner working for Wonka.

So I wonder about Spotify. It's not hard to imagine that in their quest to become the music player for the web, they could easily become the music player for Facebook, which would give Facebook a pass to use my music (and any other artists' music) to feed their massive ad machine, while continuing to provide those depressing fraction-of-a-cent payouts that has better musicians than I up in arms.

If that happened, musicians would surely grumble, but would it lead to a mass exodus from Spotify? I guess that depends if you see any value in Facebook's 850 million users suddenly having an easy way to share and listen to music within Facebook itself.

These tea leaves, they sure are bitter!