Note This feature feature is now out of date - see Message Filtering Feature Redux
Sometimes you might want to send a message to a group, but you know there'll be people who don't want it. At the same time, it's not worth creating a new group just for this message. Tagging lets you tell rhub what a message is about, and filtering lets people chose to include/exclude certain types of messages.
Example case, there's a large group called 'tennis'. Some people join the group to play, others join in for the social events (read: beer drinking). If Gisele sets a filter of 'beer' for the group, only messages tagged with 'beer' will be sent to her from that group. Jackson might set a filter of '!beer' which he won't get any messages tagged with 'beer'. Everyone wins.
Of course this magic only happens when Messaging, messages are tagged by the sender]], but it's easy to do, just put the tag in curly braces, e.g. Let's go out for {beer} tonight!</p>
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