There are two types of filters which work on posts. While one of them checks publication date of posts, the other one checks occurances of words in the content of checked posts. News Slideshow and Post Sweeper depends on the first filter type, and the second one, which is also called a word-based filter, is used to monitor and filter retrieved posts thru channels.
Anatomy of Word-based Filters
Word-based filters check occurances of special word or phrases in the post. Word-based filters are used by channels to filter out unwanted posts as soon as they are retrieved, by virtual channels to gather posts from other subscribed channels, an by even Trashbin to throw newly retrieved posts into the trashbin.
Following explains the parts of word-based filters.
AND-Relation vs OR-Relation
You can add one or multiple words to be checked for occurances. And when you define more than one, filter also enables you to define a relation between them. They are called 'AND' and 'OR' relations. If you select OR-relation, it means that post satisfies the filter criteria if it includes at least at least one of the added words. Otherwise, if you select AND-relation, it necessiates the occurance of all added words in that post.
Where to Check in the Post
Recall that posts consist of various parts, such as title and content. Based on that, you can set word-based filter so that it checks only specific parts in the post. At this current version, you can only select the title or the body of the post, other than all.
Filter Behaviour : IN vs OUT
By default, all word-based filters check posts for approval to perform the final action. For example, virtual channel filters check posts to gather them, which is the final action. However there can be cases where you like to set filter so that final action on posts should not be performed if they match with the filter criteria, which is the opposite behaviour.
These two different behaviours are called Filter-in and Filter-Out. If you like filter to apply that final action on matched posts, that filter have filter-in behaviour, which is the default behaviour. On the other hand, if you like filter not to apply that final action on those matched posts, then that filter has filter-out behaviour.
To learn more about word-based filters, check following help topics listed below.