Google's walk/run tracker app, My Tracks, doesn't get updated terribly often, but when it does, there is usually something worth reporting. This most recent update is no exception, as it now offers Android Wear support and some changes to the way sharing works.
Unfortunately, Android Wear support does not mean that you can use the app on the watch alone, independent of the phone. Since Android Wear devices don't yet support GPS, it's basically impossible to have a functioning version of this app on a watch alone. Think of this, instead, as a very useful remote control. You can start, stop, and pause your walk or run, as well as view your progress, right from your watch without having to take your phone out of your pocket.
As for sharing, you can no longer share your latest treks directly with other apps. Instead, sharing now happens via Google Drive. You can either invite specific people to be able to see them, or you can make them public and then share the URL directly to the app of your choice.
The update may be staged, so if it's not available for you yet, hit up the link down below to download the APK.
The APK is signed by Google and upgrades your existing app. The cryptographic signature guarantees that the file is safe to install and was not tampered with in any way. Rather than wait for Google to push this download to your devices, which can take days, download and install it just like any other APK.
Thanks, Rens Blom!