I have done a very initial port of the Photobook package to postgres. It's still rough and you have to apply some patches to acs-content-repository and cms to get it working, one of which requires PG7.3. I'll try to get checked in soon but for now anyone who wants to work with it please contact me and I'll give you a tarball and some hints.
Why would you want to use Photobook?
You want to collect and display profile info.
For Sloan (ie photobooks current configuration) it collect demographic info, employers, schools and degrees, several addresses and of course a photo.
Has some cool data like a huge list of schools around the world.
Users have some control over what data is suppressed from display to other users.
If you want to create functionality to manage giving your users email@example.com email addresses, the code to manage Sloan's EFL might be a good starting point.
What's the bad news?
Needs a programmer to customize, not web configurable.
Not trivial to install.
Various places in the code say "sloan" and contain very Sloan specific logic.
Still some rough spots in terms of bugs and some of them are in CMS and CR.
My next step is to customize it for another client. I'm sure I will have more good and bad points after that process.
Bottom line: seems very useful, if you are comfortable programming in OACS definitely try it out. If you're not a programmer it's not ready yet.