Being one part of the content - the deliberate categories claimed by the author - its weight in any algorithm should have a sensible default and be up for customization by the user. This can start with the general weight for all tags and be fine-tuned via overriding user preferences like, "Do not treat #actifit as a content tag for me." Also, "I want to see [less|more] of #hiveposh," up to 5 degrees or so.

Hive stands out as encouraging curating your own post with tags. My instinct is to take advantage of this, as I would also proof-of-brain stake curation, again with both parts of the weighting feature above.