Part of Microsoft's big vision for the future is to more closely integrate Windows 10 and Xbox One, and that will involve cross-platform play and Achievements (to name but two features).
The company's plan to bring the PC and console space closer together had caused some to worry that we might see Xbox Gold introduced into the PC space. However, this is not the case, and this is what Microsoft had to say when one Twitter user asked if there were plans to introduce a paid-for subscription for online services on PC:
"Not charging," Larry ‘Major Nelson' Hryb confirmed on Twitter. "Xbox Live Gold will not be required for online multiplayer gaming using our service on Windows 10 PCs and Phones."
One game where there will definitely be cross-platform play between Xbox One and PC is Fable Legends, which Microsoft confirmed last month will be free-to-play on both platforms.