What matches are exchange matches?

The match overview contains matches you have created yourself, but also exchange matches if you participate in sharing a laeque.
If you are going to upload a video to an exchange match, it will be shared in the pool.

The matches with the 'double' arrow after the date are the exchange matches. Uploading to that match means that the video is shared with the others in the pool who also participate in the sharing and fulfill their obligations.