Can Apple's earpods be used with any smartphone, or are they specific for the iPhone only ?
They can be used in any device that accepts a 3.5mm stereo headphone jack (and that's pretty much anything that has a headphone socket these days, alternatives include a smaller 2.5mm jack, or a much larger 1/4" one), although the inline controls may have limited use or operate differently depending on what you plug them into.
As to advanced features, this depends on a couple of things. The socket size is the most important consideration, but the next thing is the amount of "poles" that the headphones have, and that the socket supports. A "2 pole" device (3 separate contact areas separated by 2 solid line/band right around the jack) will provide for stereo sound (left/right/ground), adding a 3rd band/4th pole will add MIC functions and the ability to send controls from an inline controller for volume, track selection etc. For the latter, the actual commands sent down the connection may vary per device, giving you volume on one device, or tracks on another, but there are a couple of semi-unofficial standards in that it usually works OK across devices so long as the contact is there inside the socket to support the connection.
Standard Tip Ring 1 Ring 2 Sleeve Phones using this Standard CTIA / AHJ Left Audio Right Audio Ground Microphone Apple, HTC, latest Nokia, latest Samsung, latest Sony (2012+), most Android phones
This page may help if you need to read more.
Some models of Apple earbuds or in-ears like ME186LL/A were very popular in the past, have been critically looked at and are known to work with other smartphones. I couldn't find a complete listing or offical statements of which model supports which standard or if they all follow exactly the CTIA standard, though.
I got the earpods along with ME186LL/A and remember that the middle button was working on Android according to the Android specification. I still have the ME186LL/A which work the same way on Android and Windows Phone. In contrast Sony's MH1C have working volume buttons on generic Android devices and Windows Phone.
Offical statements or a crowdsourced list would be really nice to have.