We're expreiencing a really, really frustrating problem.
Right now I'm using a Virtual Dedicated server with godaddy. Our site is a social networking site that allows the group leader (groups usually of 50-75) members send out a mass email (or text) to its members.
The problem is that a lot of our users are reporting that these emails are going to their junk folders. These emails include these people's names, their group, and doesn't have any of the classic spamming content (free, save, viagra....).
I asked godaddy if perhaps someone else on the server was spamming and if this would explain our problem. They didn't help much and said I couldn't switch the ip for my VDS. They said the problem could by my content (which I don't see how this could be) or the headers...
Now the headers I use now, just from some script I copied, was this...
$headers = 'From: firstname.lastname@example.org' . "\r\n";
$headers .= "Content-type: text/html";
$checker = mail($email, $subject, $body_message, $headers);