Yahoo and Microsoft Identity Information in a Subpoena

Q: Do you know what information Yahoo or Microsoft give away if there was a subpoena to figure out identity of email account?  Do they give away actual emails or just IP logon data and personal info from registration?  How would someone stop the discovery if he wanted to stay anonymous?

A: Unfortunately, I don't know Microsoft and Yahoo's policies in responding to subpoenas seeking the identity of a person with a particular email account.  If you have not already done so, you might check the privacy policies and/or terms of service on the web sites of both entities, which might provide this information and/or contain other information pertinent to your situation.
 
The steps you might take to prevent discovery of your identifying information would vary depending on the particular facts and circumstances of your situation, but might include a John Doe motion to intervene and motion to quash the subpoena/discovery request.

In the event you are interested in obtaining specific legal advice for your situation, you might try using CFAC's lawyer referral program.  The following link on CFAC's website contains information about the program and a form for you to fill out.
http://www.cfac.org/content/index.php/cfac/lawyers_rfp/

You may also want to go on the website for the State Bar of California for information on lawyer referrals:
http://www.calbar.ca.gov/state/calbar/calbar_generic.jsp?cid=10182.