In this day and age it might be wise not to give out such information.
I am wary of anyone asking for information like this.
The only people who need this type of information are those coordinating the project and to an extent those involved in the work in sick people, you need to guard your identity just like your life.
Keep in mind some people aren't as altruistic in there endeavors, as can be witnessed by the daily tally of world events. Not saying be paranoid but be careful.
Cyb
Wait, what. What is someone going to do with a username.
First off, welcome to the forums.
Secondly, if you'll look in the bottom right hand corner of each post you make, you'll notice there is a little "Logged".
That's your IP address being logged, so I'm sure if anyone smart enough wanted to, they could easily hack the forums, get each IP address, corresponding to each username, and track through the details given in registration (which I assume are stored).
Not saying it's happening or anything, just an idea of what could happen, if any people did want to find out identies. Keep in mind, in this day and age, there are untold ways of getting peoples details through the smallest of means.