Does anyone have actual studies or more rigorous data discussing the actual technical cost to entry of new participants in various communities, based on their primary method of interaction?
I suppose that's a very general question, but I think it's one worth exploring at a variety of levels. That is, when you have a user who first wants to start contributing to an open source project - code, docs, or even just advice/answering questions - what are the technical barriers to entry, and how do they slow down the process for most users?
Apache uses email lists for the great bulk of dev, user, and community discussions. Email is the lowest common denominator, and when you include a link to http://apache.markmail.org/ it allows reasonably easy access to past mails. Thus, there's no login required at any point, although it's not always so obvious how to browse categories or structure of past conversations. While all the data is there, we don't really have as good visualizations available for newcomers to find things, some web fora provide much better tools to find past conversations and information.
Many other projects use discussion fora - either BBS/forums, or things like StackOverflow like websites. These all require some sort of login. Obviously, some federate to various common logins like Twitter/FB/Google+, but many still require a separate login, which we all know is a huge pain, especially to newcomers. Both at first step, but also: how many people login, participate for a short time, but then the next time they come back to participate, they've forgotten the login, and give up then?
Besides all of our many anecdotal stories and personal preferences (or religious wars) on the subject, are there any surveys or other data on the subject?