When you save a Site Template in SharePoint you can specify a Description. That’s fine – but doesn’t really seem to be used anywhere, other than a little note on the ‘Create new Site’ form (see below). I’d always assumed that it was. Well, I was wrong.
It turns out that if you set a description in your template…
…and if you leave the description for your new site blank when creating it using that template…
… then the new site’s description will have the Site Template’s description…
That seems like a bug to me – a Site Description isn’t the same thing as a Site Template description.