CiviCRM Community Forums (archive)

Tracking of opens is based on whether the recipients’ email programs display invisible, 1×1 pixel images from the server; this method is not foolproof, as the readers must (a) use the HTML version of the email, (b) their email clients must allow displaying of images from remote servers and (c) there must be a live internet connection between the recipient and the server at the time of reading. Still, we didn’t come up with any better method. :|

As for tracking of click-throughs, an un-tracked click-through is a bug; if you could track down an narrow the problem a bit more, do file an issue in our issue tracker.

Thanks Piotr, that's helpful. So if people looking at the mailing see the pictures as red crosses and don't download them, these people aren't tracked either?

Yes, they’re not tracked.

Do you by any chance have any figures about what proportion of recipients are successfully tracked?

I’m one of the old-fashioned geeks who uses the console-based Mutt client, so I’m not really too strong (nor too fond of) HTML email in the first place.

That said, my guess would be that the ratio of proper open tracking is strongly tied to the proportions of target addresses. I’d guess you can assume 95% (or more) of @gmail.com recipients use their webmail, maybe the same for @yahoo.com, while, say, most corporate users would end up opening the emails using more-or-less default Outlook configuration.

I know I didn’t answer your question, but maybe I pointed you in the right direction…