When I send a mail to a user using the "Contact" button on the user's page, the sender is set my email address. But the email is being sent from SlideMe's server!

This causes the email client of the recipient to flag the email as a "possible phishing attack".

It would be much better if the "From" header was set to something like "no-reply@slideme.org" with a "Reply-to" header set to the sender's email address.

This will ensure that them email is not marked as a phishing attack as well as ensure that the replies go to the sender directly.