Version 5.53B4 and newer have a new facility for filtering headers from the stream of data downloaded from the server before the posts are saved to disk. Here's how it works:
You have a Group of Groups (GOG) named "Automobiles". In this GOG you have a number of groups related to cars. Lets say you want to filter out "chevy" but keep everythng else.
1) Create a new filter profile, name it whatever you wish and add "Chevy" to the Subject reject part.
2) Edit the NBI file with wordpad.
Add this entry to the GOG. Just use the name of the filter with no greater than signs.
Save the NBI.
Start Newsbin. When you update the group, all the groups in the "Automobile" GOG will have header downloads matched against the filter profile and rejected items will be rejected (as reported in the logging tab). Accepted items are stored on disk.
The benefit of these filters is you can keep the groups clean and as you notice spam patterns, you can add new filters to reject things you don't want. These filters increase load speed and reduce disk space.
The downside is, if you're not careful you might filter out posts you want and NEVER see them.
If you use regular filter profiles you can always turn them off and see the filtered out posts. These filters are DESTRUCTIVE. The only way to see posts you've filtered out this way will be to REDOWNLOAD headers from the group again.