i think the website should allow people to accept co-authers on forum pages
in Steam, the author of a guide is able to invite people to be Collaborators.
In this example you see here, i asked Nick to let me help him up-date his guide. It was outdated and he said in his comments section that he had lost interest and the motivation to continue keeping his guide relevant.
When i accepted the invitation, i had nearly full control. I can do everything but invite/remove other authors and i can't delete the guide itself. I can do virtually everything else and after he invited me he found maintaining his guide much more interesting. We got on Skype and worked on the format, fixed some old information, and otherwise got the guide back into fighting shape.
So i'm saying implement something similar for forum pages. A lot of these modding authors go away, have life, just lose interest, or otherwise need help. Without being able to let people in to up-date the page it's hard to get that help in some cases. either way, i've seen a couple forum pages were i'm sure the authors would have others on board with them if they could.