Scrap Prodromus as chat support framework and use Qwebirc
Based on the volume of emails the support desk receives, I'm concerned that the support team could quickly become overwhelmed with requests for private chats using Prodromus. A private chat system could quickly become more popular with users than the Tor Project is equipped to handle, resulting in frustrated users.
Qwebirc is a Javascript IRC client. http://qwebirc.org/ It acts as a web portal to any IRC channel.
Most of the work here is already done. All we would need to do is link to http://webchat.oftc.net/?channels=tor or http://webchat.oftc.net/?channels=tor-support if we want to make a support-specific channel.
Digital Ocean uses exactly this model on their website. A chat button on their site's banner links to: See: http://webchat.freenode.net/?channels=digitalocean&uio=d4
Note that freenode includes recaptcha_ajax.js as part of the interface.
Using Qwebirc does not even require setting up a VM, although it could be set up as a private instance on the Tor infrastructure, if that's what we wanted to do.
A previously expressed concern with using IRC is that it's hard to get on IRC. Normally, one needs to download and install an IRC client, and, if one is using Tor, configure the proxy settings. This is too much to ask of most users.
With qwebirc, the browser is the client, so joining IRC is as easy as using a web browser, and connecting over Tor is as easy as using the Tor Browser.
A drawback of using IRC is that support would not be private. I think this is a good thing though. Besides making support more transparent, Tor users will have the opportunity to lurk, to learn from other public support requests, and maybe to fix their own issues as they see how others' issues are resolved. If they use the Tor Browser, they will already be anonymous.
A benefit of using IRC is that we will be able to leverage the support of the community. If a user wants to chime in and offer insight for another user regarding a support issue he or she previously had, that helps us.
If support chats are public, users will queue themselves, because there are only so many people who can talk at once.