@paulag - measuring growth on steemit can be quite tricky when you don't have a steady or routine pattern of posting, or if you are posting in multiple categories like I am at the moment. I think for new people the most important factor seems to be the number of followers, in particular the reputation of the followers like the data you get on steemtracked.com (they call it Audience):

I still think comments and upvotes are a good long term measure of growth if you have been around for a while and have a steady following, but the payout is easily affected by the voting power of the person that sees the posts. And anyone with a lot of voting power is likely to see a lot of posts without necessarily wanting to dilute the power/value of their vote so I do wonder if different whales have different preferences or strategies (I would like to read about it if they ever write something like that).