The problem as I see it is I can click through a few buttons and then I get to the last "Tell me More" and it points me to a wiki page, with lots of missing sections, half paragraphs, unfinished bullet points etc. Then there is a link to a bugtracker, on a different domain, with no introduction text, then contributing to the source code is on a different site, with yet another profile to fill in (Once you have gone through the Wiki, Bug Tracker ++ !)
Actually I guess my main problem is lack of concise, consistent "Getting Started" documentation (Not just Mozilla, nearly every project - in fact Mozilla is far better than many!). Yes, I could read through pages and pages of wiki but, let's be honest, it's ugly and in some cases badly organized - it just gets the job done (let's somebody who is interested in getting involved in that project find some information they need to bootstrap themselves), rather than lure in new developers.
I know many, many excellent developers who would love to try their hand at open source, but simply are not going to spend the hours/days necessary to trek through wiki articles to find what they need, especially on projects they barely know about (Mozilla's Build and Automation tools for example - not public facing, but many many devs have an interest in this area and would love to work on something like that)
In an attempt not to just complain, I will offer a few ideas, please steal, iterate and implement!
A Dashboard - What are people working on, talking about, planning to do now? What are their blockers? I see so many projects with a Project Website, Wiki, Development Wiki, Bug Tracker, Source Code, Road Map, Discussion Forums etc. All with different branding, not linked together and without actually finding the default page you become lost.
Digging further, who are these people, what parts have they worked on? Who can I ask about a certain section of code (git annotate?)
Bring developers, testers, writers, artists, support etc. together in one place. When a new feature is being planned, be able to co-ordinate, form a mini strike team and go!
Build a style and a community. I see far too many default Bugzilla themes in open source projects. Which is great and fine when you are small and starting out and need to keep track, for someone new wondering around your docs suddenly faced with a blank bugzilla theme with zero branding information anywhere.
To summarize: Bigger projects need to do the follow to their on boarding new contributors documentation:
Have It. Brand It. Simplify It.
(And yes I know, the problem is time and money! But one can dream...)
(PS, If there are any projects that would like a C++ programmer with a passion for documentation, give me a shout!)