There isn’t a unique engaged level. Choosing 1 month as a good timeframe, we have to split into
- passive (read a lot, no post)
- sligtly active (read a lot, 1-2 post or % )
- active (read a lot, at least 10 posts and 20 visits)
- power user (regular)
If we wanna talk about just one metric, posting at least 1 time in the last month is “engaged” for me.