I just ran across this very interesting email tracking service:  www.WhoReadMe.com.  Essentially, the service will allow you to do some limited basic tracking on emails that you send, for free.

I say “limited” above because (1) its only truly “free” for your first 20 emails per day, and (2) their email tracking is still handicapped by all of the same pitfalls as all of the other tracking services, which include:

• If the recipient’s images are turned off, then none of the tracking will work at all.
• The number of forwards/opens/unique-opens is inaccurate if multiple users are behind a corporate firewall and all have the same outward-facing IP address.
• The metrics about browsers and operating systems requires that the recipient be using a web-based email service like hotmail, yahoo, or gmail.
• Cookies are used to track some metrics, which don’t work in most email clients that are not web-based.
• You are dependent on their network for the tracking, and if they experience a network failure, the tracking will not occur during the outage.
• Cannot truly track if an email is “read” or not.
• Cannot determine if an email was delivered to the inbox, the spam folder, the trash bin, or quarantined in a spam-filtering system.

In short, this system has all the same Achilles heels as most of the other email tracking solutions, but since this one is free, it’s a pretty good value.  I point out the limitations only because people who may not be so tech-savvy may not understand the current limitations of technology.  The current trend in online marketing is to rely heavily on these kinds of metrics, so just be sure you know what’s really happening.