4. Content of the Service. Google takes no responsibility for third party content (including, without limitation, any viruses or other disabling features), nor does Google have any obligation to monitor such third party content. Google reserves the right at all times to remove or refuse to distribute any content on the Service, such as content which violates the terms of this Agreement. Google also reserves the right to access, read, preserve, and disclose any information as it reasonably believes is necessary to (a) satisfy any applicable law, regulation, legal process or governmental request, (b) enforce this Agreement, including investigation of potential violations hereof, (c) detect, prevent, or otherwise address fraud, security or technical issues (including, without limitation, the filtering of spam), (d) respond to user support requests, or (e) protect the rights, property or safety of Google, its users and the public. Google will not be responsible or liable for the exercise or non-exercise of its rights under this Agreement.

Mind the parts where it states that it "reserves the right at all times to remove or refuse to distribute any content on the Service, such as content which violates the terms of this Agreement. Google also reserves the right to access, read, preserve, and disclose any information as it reasonably believes is necessary". I guess other providers do the same, but I'm still glad I'm my own provider concerning email traffic.

Heh, talking about GMail; Slashdot now has an article about Hotmail blocking GMail messages:

"Emails and invitations sent to Hotmail from Gmail accounts do not bounce, but nor do they arrive in the recipient's Inbox - they vanish mysteriously into the aether."

The autor hasn't been able to verify this but it's interesting nonetheless.