I have seen a general plateauing of my series at least in terms of new subs, views, and comments. The growth is still there, but it's pretty slow going. However at the same time I see a lot of great new series popping up, and other series from elsewhere on the internet starting to post here (and subsequently get a healthy start with a Staff Pick off the bat). Tapastic does its best to encourage newcomer creators above a certain threshold of some invisible measure of quality, and I applaud that, but not as much to retain them I feel.
Established series have a good critical mass of readership, new series get priority on Staff eyes, but existing series with a small to modest following have to make do with at least the fact that the overall user base is increasing.
It would also help if the Snack had a bit more variety. Don't get me wrong, I love RandoWis to death but it seems like every update gets a Snack when I feel like it should be more about discovery of less read series.
In the end, I'm not leaving Tapastic anytime soon since I really love the overall atmosphere here, but I might shift my focus more to the LINE side due to better visibility, more comment activity, and steadier growth.