We at DoTogether have been experimenting with Facebook applications for a long time and have a fairly good idea about the internals. Most of the concerns are unfounded and baseless.

I wanted to share our perspective on the related Privacy issues. 

#1. The general nature of the privacy problem is not new to Facebook. If you ever have wanted to do something social, you have to bring friends and family into it. 

•  If you have emailed someone, you have had to give Yahoo/Google their Name and email address. Which actually they use to run ads.
•  If you have used Evite, you have told a bunch of people to come to some place. Also given out their name/email to Evite.com
•  If you have a phone, you will be listed in whitepages.
•  The place where you live is on Google maps with street photos and turn-by-turn directions.
• If you bought something online or offline, you have given out your credit card information.

#2. We still use these apps because they provide a service that you want and that service requires some "minimal" amount of data

• In most cases the apps can only get information such as Name and photo of your friends.
• For anything more, Facebook requires app developers to "ask" for specific permissions.
•  Did you know? Facebook never gives out your email address to applications. They just give a proxy email address and send all email themselves on behalf of the application to you.
   

#3. Golden Rule of Online Presence and Safety still applies no matter what you are doing online.

      " Watch what you are typing and sharing" - whether it be in your email, comments, wall postings, photo sharing.

Lastly, at DoTogether, we let the user decide. The user has to specifically invite friends or post stuff on their wall or share their email address with us. Every thing is done so that you can do more with your friends than chatting and sharing photos.

Rahul@DoTogether.com

 Our facebook application : http://apps.facebook.com/DoTogetherMall - A social application to get shopping tips from friends. Thousands of products from all the popular stores like Forever 21, Target, Macys, Nordstrom and many more.