Gabriel Marinescu said
1 year, 4 months ago: @pacey First, I have to thank you. Regarding interacting with your fans I learned a new “trick” today. This ideea of a caption contest, and variations on it, seems it could yeld some nice result. I don’t know how many people use it, but I never an into it, never read about it and so on. So thank, I learned something new. 
”of the new fans, how many did you manage to keep as engaged users?”
First, re-reading this thread i realize i made a mistake. I read about a big contest which brought in quite a few fans and when i replied to you I asked you about it, even though it was not your contest.
Secondly, I was mobile and I (still) dislike typing long messages on my phone.
If the conversation is started… let’s go on with it.
What I thing it would be an ok-ish way of measuring the ROI in engaged fans is this: before the contest you had an average number of engaged users. Let’s say 1k. This was the loyal community you started with. During the contest you get to 2.5k. One month after the contest ends you end up with an average of 1.8k that still engage with your brand. So i’d say the ROI in active users in this case is of 800 fans.
Would this way of measuring be wrong? Anyone knows a better way?
Have a great day!