It's typically refered to as a 'web bug'. It's used by a lot of sites, as it forces the client to make a connection to a completely different server, that may not even be in the same domain. This allows them to use one system to collect usage statistics for many web servers. And because it's not loaded from an SSI, there's a HTTP connection to the browser, so that cookies can be placed, as well. (note -- some browsers can be configured to reject cookies from images that aren't in the same domain as the page)

Some browsers can also be configured so they specifically don't download 1x1 images at all. (I know iCab has had this option for many years)

And personally, I'm against HTML for all email, but you're right -- this is just one of those many things that makes it even worse. But this item isn't just an email type thing.

Update: based on the script name, it might be the following. (I'm not making it linkable... no sense in getting their page rank higher)

• http://www.script-directory.net/perl-scripts/mail-visitor-info-details1397.html

It is always safe to quote values in HTML elements, and I would recommend it.

<img src="http://www.domain.com/cgi-bin/mvi.pl" width="1" height="1" b
+order="0">
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