Receive a notification when the user open an email - Ruby On Rails

I building an application using rails, and I wanna know if is possible
to write a code which allows me to be notified or something like that
when the user open an email sent through my application. I need to track
that information. When I sent an email, I need know. The question to be
answered by my app is "Did they read it?"

Tips in others languages would be ok to me!

Thanks in advance, and sorry for my bad English =))

I building an application using rails, and I wanna know if is possible
to write a code which allows me to be notified or something like that
when the user open an email sent through my application. I need to track
that information. When I sent an email, I need know. The question to be
answered by my app is "Did they read it?"

You can't know this with certainty. The most common technique is to
include a link to a tiny image and log requests to the image
(obviously include enough in the url that you can workout which email
is being read). A lot of people have external images turned off for
their email though

Fred

See SendGrid
http://sendgrid.com/

They have "open" notifications when you use HTML templates for the
emails.

I building an application using rails, and I wanna know if is possible
to write a code which allows me to be notified or something like that
when the user open an email sent through my application. I need to track
that information. When I sent an email, I need know. The question to be
answered by my app is "Did they read it?"

You can't know this with certainty. The most common technique is to
include a link to a tiny image and log requests to the image
(obviously include enough in the url that you can workout which email
is being read). A lot of people have external images turned off for
their email though

For precisely this reason.

Walter