Hello, and thanks for your interest.
1. I'm not quite sure what is meant there.
Phone home? If you mean, that if there is any part of code which provides extra connections to 3rd party domains (incl. minibb.com), except for the primary domain where it's installed on, the answer is definitely "
NO".
It doesn't load something from 3rd party websites, it doesn't contain stats or banners or external JavaScript code/apps, the same I can tell about all add-ons. It's one of the reasons I've programmed miniBB, so it doesn't contain any viral codes (at the same time mostly every free software will contain them). It loads all data from the local domain only.
2. You can optimize templates and CSS, removing all newlines and spare spaces; on the server itself, you can install Zend optimizer/Zend cache - but honestly, it won't bring lots of breathing. May be you can save about 5-10% of traffic with that, and not quite a lot of resources.
minBB's code to output is extra-clean already, it's coded manually in a plain text editor, which doesn't add anything extra-specific, so it's simply nothing to clean from. I believe that even using solar-powered computers means much more energy and speed involved that it was in Modems era. And I was successfully using miniBB even sitting on a slow-connection modem of 14,6 Kbps.
Considering bandwidth issues - viewing properties of any page miniBB outputs, you can see that even the first page (most heavily loaded) doesn't go beyond the size of 100 Kb. It most cases, it's even less (60-70 Kb). It's an average JPEG quality picture size. If you check the upcoming
Mobile interface, it will take even less.
Let us know about your progress :)