Edit: I'll just note that considering the presence of peaks, probably median would be a better indicator than average. Hell, a whole distribution would be pretty informative lol, but that's probably too much info..
I mean, mean is better than median in that if you multiply it by time then it gives you the sum.
But mean over what period? It's a bit complex.
I think that probably @csallen was using "peak" because some of the projects had since gone defunct and he wanted to count them. Although I think in such cases it would make sense to do an average of the best year or something like that.
For projects like mine (https://complice.co/) which are still growing, "peak" is also weird, because it suggests that... I'm not still growing? I'm not even sure. At any rate, it doesn't make sense to use my average over the last year if my average over the next year is going to be twice as much. Better is probably just the total of my active subscriptions.