I can think of a few tweaks to filtering that would make Limewire just a whole lot more useful to me. The existing features are really quite good, but there are a few things that I think would help.

1.) Stop nuking my filter settings every time a new version of Limewire is released. The adult content filter is pretty good, but it (understandably) misses a lot of things. I like to build up my own filters, and the list can become rather large. This makes it really a pain to rebuild every time a new version of Limewire is released.

2.) Allow filter settings to be imported/exported, or saved in a file separate from the rest of the configuration settings. This could be a solution to problem 1. If I could export my filters before upgrading and reimport them afterwards, the problem becomes minor. This would also allow people to trade filter lists. For example, if someone wanted to make a very thorough filter list to block out Britney Spears mp3s, or a list of hosts known to be distributing vbs virus code, etc.

3.) GUI host blocking. Currently Limewire allows me to enter IP addresses of hosts to block, but doesn't allow me to do this via the GUI. An addition to the right-click pulldown seems like a good idea.

4.) Regexp filtering. The current substring-based searching could be made much more powerful by including regular expression matching capability. There is probably already code out there in Java that does this, and it may even be licensed such that it's usable in Limewire.