Shapeshift.io Cryptocurrency Exchange

Shapeshift.io allows you to exchange and swap cryptos for cryptos depending on availability you can trade #STEEM for #BTC or #XMR or #LTC and many more depending on current availability

#Shapeshift also acquired Bitfract recently and it is one of the leading crypto exchanges with low fees and fast turn around times

They also have a fascinating "no fiat" policy, meaning that no fiat currency or banks are used in their operations.
However depending on how you feel about certain investors though #shapeshift may not be for you:
Earlybird Ventures
LakeStar
Access Venture Partners
Pantera Capital
Blockchain Capital
Digital Currency Group
FundersClub
Erik Voorhees
Roger Ver

However for the service provided it can help produce liquidity among different cryptos instead of allowing markets to stagnate.

They also have an opensource tool called Skeleton that allows any website to implement instant sale of digital assets and cryptocurrencies.
https://info.shapeshift.io/tools/skeleton
Shapeshift is also on mobile devices.