1.
The filters are only applied to feed articles which haven't been 'read' yet. Once you read them the filter stops being applied.

2.
The filters are only applied to feed articles which have a <title> component. I subscribe to a feed which doesn't have a <title> component in its code so being able to use other parts of the feed would be nice, such as <description> etc.

3.
Feed specific filters would be nice too. The script could save filters for each specific feed and only use them on that feed. Being able to choose options for each feed would be nice too (e.g. whether to use the <title> or <description> component for a specific feed).

Aside form that, it is a good script, just needs a bit more work. If i could code Javascript, i'd do it myself.

Cheers

NM</description></title></description></title></title>