Will subpoena to Blog*Spot reveal user?

There has been a long-running feud between two parties. Who they are and the nature of the feud are unimportant. You can read about it here if you want.

What is important to bloggers is the threat to reveal an anonymous blogger by trying to force Blogger's Blog*Spot site to fess up the real name and address of it's user. In an email threat, one side said: "Determining your identity for the purpose of making service of process can be easily accomplished through a subpoena to Blogspot.com." Will Blog*Spot cave under the pressure? This will be something to watch as two parties that you ordinarily could not care less about force some real privacy issues on the blogging community.