That's just it, the link is dead; I can't upload anything, even though I have much more data now, especially since I started Archeology and am questing and gathering on the Broken Shore.
I do upload to WowDB and Wowhead via the Twitch app and Wowhead Client, but Nevcairiel hasn't parsed the data in quite some time.
In the Twitch app (used to be Curse App, and Curse Client before that) click the big cogwheel at the client's top right, then Settings, Addons, General (not game specific) and at the bottom enable WowDB Profiler. I am not 100% certain this is working, and I did send a bug report to Twitch/Curse because it says last updated "never".
To use the Wowhead Client, all you have to do is install it, and it adds a new addon which gathers data. Check the client's settings on how and when you want to upload, whether automatically upon game exit, or manually when you remember.
The only other method of updating GatherMate2_Data is spamming poor Nevcairiel with file links from your Dropboxes, but I am fairly sure he would not appreciate that.