I have been following MastCoin and CoinRecycler development for some weeks now and correct me if I'm wrong but I think we can honestly say it will start something big in altcoins.
Here is why :
Right now to buy/sell our coins we all need online accounts on exchanges, with emails, phone numbers for 2FA... we need to wait confirmations for deposits, withdrawals, need to wait for an order to get filled, need to take care of not holding too much money in the exchange...
But what if I tell you all of this will be old history soon ?
CoinRecycler allows you to sell your coins for MAST through a fully anonymous and automatic process, you only need to select the name of the coin you sell, the number of coins, then the coin recycler calcul the number of MAST you will receive, you put your MAST adress where you want to receive the coins, generate an adress to send the other coin and you will receive some MAST in around 30 minutes.
CoinRecycler is available here and support 5 coins
http://recycle.mastcoin.org/In only some days it will be implemented in the wallet, will support some new coins and of course support BTC, maybe in both ways so you can buy and sell also.
An API is also ready for integration in a website.
So I think this is a really good feature, because it will be a lot more anonymous, not any online accounts needed, no exchanges where you put your email adress, phone number...
And of course a lot more secure than using exchanges.
It could also help to bring mass adoption because it's really easy to use (all in one)
Of course this is my own analysis, I think it's worth sharing it here but do your own before investing