You need to upload the files to some place. He's saying with app net it's possible to upload it to the network (like Twitter) itself, and not to some third part

You need to upload the files to some place. He's saying with app net it's possible to upload it to the network (like Twitter) itself, and not to some third party storage like dropbox/mega/box. Just like sending images on Twitter. And regarding "just send the link via DM", that's currently not possible any more: https://dev.twitter.com/discussions/23044 https://dev.twitter.com/discussions/23044