I was just posting on Steemhunts post about working with an exchange to get a base pair. Honestly, if someone was in the community that had the tools/know how to set-up an exchange on the Steem blockchain that could be huge on 2 fronts. One it would give a place for people on the platform to buy and sell SMTs. Two you just had the Cryptopia hack/exit scam throw some of those crap coins on the exchange and you're creating a steem exchange that brings over some Shitcoiners, but this is probably a huge undertaking.

Another future app I'd like to see on Steem is a streaming service for mobile games. There are a few options currently from non-crypto companies but would love a twitch for mobile gaming on the blockchain, but this is a very niche dapp.

I think @actifit has the highest potential of any app currently. The medical industry is big business and if they can team up with the right partners it could bring big money to the Steem platform.

If @steemmonsters can become the next hearthstone or magic. IMO it's currently a great Blockchain TCG. If it can become a great TCG this could bring a significant amount of people as well, but even if it's the best TCG ever you're only attracting users interested in Trading Card Games.

In the short term I think a dapp that allows you to instantly sign up on the platform that "gamifies" the initial account creation process rewarding small Steem or SP delegations for a few months for filling out about in user profile, including a link to a website,etc. Kind of what I explained in this comment. Streamlining account creation is a must for mainstream adoption.

I think it will be the next Amazon type business to bring Steem mainstream. Hey I have a bunch of Steem Power setting around let me log on to my Steemazon account and see what delegation requests is paying the most returns. Hey I made x steem on my returns last night, I wonder if I have enough steem to purchase that new gaming computer I want to stream on. Dang barely not enough I wonder if I can pay someone to find and build me a computer cheaper than that, let me write a quick "post" to see if I can pay someone to do this for me cheaper. The dapp that will bring mass adoption will be the dapp that people can't live without

Maybe I should have just wrote a post and replied with a link to my post lol.