Filters are a great way to help curate the content that is coming in from your various sources for your newsletter. Filters are divided into two groups: include and exclude. The best way to think about this is topics, keywords, phrases you would want included in your newsletter versus topics, keywords, and phrases that you would not want included in your newsletter.
For example, if your newsletter is focused on animals, but specifically jungle animals, you may apply include filters to your general sources that are specific to jungle animals such as monkeys, tigers, and giraffes. On the other hand, if your newsletter is focused on sea creatures, you may want to apply exclude filters to your general sources that are specific to non-sea creatures such as racoons, opossums, and foxes so that articles about those animals are not brought into your article pool.
For example, if your newsletter is focused on monkeys that do charity work, you may add include filters such as charity work, giving, and nonprofit. On the other hand, you may add exclude filters such as for profit, privatized, and uncharitable.
Filters can be controlled in two ways. The first way is to add your filter and then select the sources you would like the filter applied to. The second way is to view a source and then select the filters that you would like applied to it. You always have the option to turn a filter on or off as well.
rasa.io recommends adding filters to large, general sources. It is rare to need filters on your own sources such as your website, twitter, etc.