Someone would have to make archives of all topics of projects. It's big manual work, who are going to do that? We would need some volunters who will actively watch announcement board and make archive when new thread was published. I don't know, maybe there are some ways to make this work automated.
Something like what Vod has traced several forum statistics, such as merit, trust, activity count, postcount, account's security factors (password/ email changed).
Of course, a big database for it needed to do this.
And, one or several experts with enough skills and knowledge to do this.