It is going to be huge and I mean this in all sincerity. The market is so big and it is primed for something like this. To get 400 active users per day is not a lot once the word starts to spread.

I'm hoping growth will be slow and steady like a trickle. If it's a deluge then who know's if Hive will be able to handle it. The LightningDB helps but I think there's a point where the actions queue gets overwhelmed with a backlog of transactions to be posted to the Hive blockchain. That would be a good problem to have though as it would mean the microblogging had gone viral. But honestly, a slow and steady trickle is better.