I have been able to export and activity and would now like to allow someone else to import it, how can they do that? We went for a run and he didnt have his watch so I said he could have my trace...I cant be the first.:)
As long as you've made your activity public, they should be able to export the tcx file the same way you would. Just give them the link to the activity.
Unless you have access to their account, only they can do that. They should export the activity from your GC so they will have the file on their local computer, then they can import it into their own account using the manual upload method.