Editing the articles to improve the content, accuracy, writing flow
Making blogs/comments to start discussions
2) The live chat is largely inactive but you can feel free to discuss the show with anyone on this wiki by leaving a message on their wall or making comments on pages. Many of us are still happy to discuss the show. I'm not aware of a discord server but there may be, and there are fans on sites like twitter/tumblr as well.
3) No petitions on the wiki but you can search them, like on change.org. It's a long shot though given that the show ended a long time ago, the cast has moved on, and Dan is not working with Nick anymore.
I suppose so. Though Ariana Grande did plead for Dan to revive the show and Dan retweeted it. Hopefully it’ll happen some day soon or perhaps not. But then again, it’s a long shot and it was worth watching it. Thanks for the advice though.