About General Interests
The Interest Profile you start out with covers many topics of General Interest.
Ideally, an Interest Profile should include every topic - every country, city, occupation, subject... In fact every word and phrase should be included. This would make the most complete profile and give the most accurate results.
Of course, this can't happen for practical reasons. For every article NewsBrain evaluates, it has to scan its text for matches against every topic in the profile - for just 100 articles, that's at least a couple of hundred thousand scans. The topic matching process is by far the most time and resource consuming part of NewsBrain.
So, the general interest set of topics included many things, but some countries, cities, sports teams, and lots of other things that may be of interest to you are not included.
You can add your own interests to the profile, and if they are about things you are very interested (or disinterested) in, it can improve NewsBrain's predictions significantly.
There are probably many topics you are apathetic about and leave at zero interest. Deleting them can speed up NewsBrain and save on battery life, because NewsBrain scans for relevance to those topics even if you have zero interest in them.
It's even possible to make your own profile from scratch! With only a few topics, NewsBrain can really fly, but the scope of articles it brings up will be narrow. This can be an advantage (focus on favorite sports and teams, for example) or a disadvantage (getting nothing BUT sports and team articles).
You can make several profiles and select which one you want to be active at any particular time, on the Profiles Screen.
You can add and delete topics on the Topics Screen.