IPhone & Apple Mail Privacy Hole
secure.grepular.com
secure.grepular.com
Also, I don't think the iPhone has the option to disable loading of remote content in HTML email at all (IT SHOULD), so no bug there.
It's a great improvement, but I wish there were an option to load images on a per-message basis, like on the desktop.
I was running Little Snitch and while reading a specific email message, Little Snitch told me Mail.app was trying to connect using port 80. I denied it, but never tracked it down.
This is different than .mac addresses -- Mail.app will connect to .mac when you receive mail from someone with a .mac address (to verify if they're online, which you can disable I believe)
At least, this is what I tell my clients when recommending turning off HTML content from untrusted email sources.
I don't see it as a big deal personally if a sender of email finds out if it was opened or not.