well Im not really sure when it happened the first time, but Ive been paying more attention to individual page statistics vs the series as a whole. I have a story based webcomic though, so Im a bit different than a "gag-a-day" types ^^; so my most viewed pages are the older ones, since thats where the story starts!
the last page that has 1k+ views was posted about 3 months ago though, so at my current rate it takes about that long for each episode.
But growth is generally slow, but exponential!!
for example; after 6-7 months, I was at about 150 subscribers. In the next 7 months, it was 500. And now its been 6 months since then and I'm almost to 1000 subscribers.
Before tapastic I posted just about everywhere trying to gain followers here and there. I keep it to just a couple other places now, and keep my tapastic page a page or two ahead of everywhere else and let all my followers/watchers/subscribers on those places know that they can read ahead here!