Mobile is experimenting with showing a small banner at the top of the main page that prompts logged in editors to help a page in need of new links:
https://en.m.wikipedia.org/wiki/Main_Page?mobileaction=beta

I think this is _great_ and started playing with it on the train with nothing to do.

Two improvements need to be made though:
1) It's difficult to know what to link to. I wrap words which I feel should be existing wiki pages but I pretty much have to guess or open a new window to check those. Some kind of search interface or link validation tool/corrector would be useful.
2) Since red links are turned off in the editor preview it can be tricky to know whether I caused a typo or linked correctly if new to wiki text. This is a bad first time user experience. Some kind of validation step or feedback when I create red links in the editor itself would be useful. We should at very least enable red links in the editor preview.

On a side note:
I really think we should give more priority to enabling new page creation on enwiki to help those sort of experiences before continuing down this path of encouraging new editors. People could start drafts, start pages with photos. This seems like a really useful focus of time.