One facility which is needed is to be able to be notified of new posts which contain a particular keyword. I won’t generally have time to keep an eye on new posts but would like to be notified whenever KAlarm is mentioned, so that I can help users with issues. Without such notifications, I’m unlikely to be aware of their questions.
Current categories/topics/tags are either too broad, or not applicable, to set up the notifications which I need. No doubt the list of topics/tags will expand, but that doesn’t help just now. But in any case, keywords are a more sure way of finding posts, since topics/tags depend on the poster’s choice.