From IRC:

13:20 < Scytale> Hm. Would it be hard to change that to the other behavior,
where ignore-article will just not display matching articles? Because then
one could 1)
                 add filters without having to remove matching, already
existing articles manually and 2) remove filters if one decides that the
ignored articles
                 aren't so uninteresting at all
13:20 < Scytale> (or if one has just fucked up the filter ;)
13:22 < Scytale> Actually, when I think about it, it might be a lot easier
to implement something like automatically applied filters; you can
predefine filters since
                 0.7, the only thing that's lacking is a kind of
"automatically use filter X on feed Y whenever I display it"