[jnorthrop]

On the issue of trust. You are asking people to give the site their personal information, but you have no privacy policy -- a big no-no. And, given your statement above, anyone could join a group and then collect the information of the other participants -- another no-no. Technically, in the US, there is nothing illegal about that but you really should at least disclose that to users before they sign up.

Briefly, best practices would suggest you let anyone signing up know exactly how you intend on storing, sharing and using the information they provide. You should also get explicit consent to do so when they sign up.

My email is in my profile. Feel free to contact me directly if you want a clearer explanation.