I think this could be a good idea for Steem and also for me because since I found steemit about 900 days ago I've been here just about every day reading, voting, sometimes replying, and sometimes posting. Since all that data except for reading is on the blockchain, once a formula is agreed upon, it can be retroactively calculated from historical data. Steemit Incorporated came up with the reputation score, and now there is a steem-ua number. I'd like to see a loyalty number added to that collection.

Maybe a sum of the weighted averages of voting, replying and posting history. We would just need to come up with numbers for the weights and for the number of days we used for the weighted average. A 30-day moving average might work, and if we weight posts at 50%, replies at 35%, and votes at 15% that might work. Add in a squashing function so that the number stays within a range, and it gets harder to level up at higher levels, but easier at lower levels, like an S (sigmoid) function. Just some thoughts inspired by your post.