Bluetooth is one of the most ubiquitous wireless communication standards on the planet. It's also quite versatile - Bluetooth can be used for a variety of functions, anything from file transfers to smart accessory connectivity to tethering to audio streaming. It's better at some of these things than others, though - Bluetooth file transfer speeds and tethering, for example, are notorious for their low speed and general unreliability.
This weekend, I'm asking you: what do you use Bluetooth for? When I started thinking about how often I used it, I was kind of surprised. I use Bluetooth in my car for phone calls, for music streaming in my car, for music streaming to a Bluetooth speaker in my apartment, and for my Android Wear smartwatch [obviously]. While Bluetooth does get a bad rap sometimes for being a bit of a "round peg, square hole" in terms of its optimization for certain tasks (or battery-sapping uses like Bluetooth beacons), it's nothing if not reliably extant on many products.
But with the increasing prevalence of other standards and adaptations of existing technologies like Wi-Fi to some of these roles, a not insignificant number of Bluetooth's advantages are slowly but surely evaporating. So, what do you use Bluetooth for on your smartphone these days? I remember when I had my Nexus One, I actually did use Bluetooth for file transfers occasionally (before Android had Wi-Fi direct or Android Beam). Now, I tend to limit Bluetooth to situations where it is essentially necessary.
I'd certainly be interested to hear more from those of you who select "other" in the poll, as well, so be sure to comment if you've got a particularly interesting Bluetooth use case.