[PHP] using mail() - what is max number of email addresses I can specify in To field?

I am writing a script that will query a database table for some statistical information, and then email it (daily, weekly, and monthly) to a list of subscribers. I don't know ahead of time how many persons will be subscribed to receive the info (it could be 20 persons or 2000 or more). Email add

[PHP] Is PHP used by U.S. Government? By U.S. DoD?

I would like to use PHP in a project for a United States Government client. The client is skeptical because PHP is not a Microsoft product. I'm looking for statistics and links that show that PHP *is* currently in use by the US Government. Is PHP used by the U.S. Department of Defense? Exampl