You may have noticed that there are actually two terms here and that they are completely different.
STEEM = The currency / Blockchain.
Steem is the currency that can be freely sold and bought in the digital currency markets. When we talk about Steem from a more technical point of view we are also referring to the Steem blockchain. Steem is a coin just like Bitcoin, that is to say that it is censorship-proof and totally decentralized.
STEEMIT = The site that accesses the Stech blockchain information.
The site Steemit is just a vehicle for you to access the blockbain Steem being good to remember that the site Steemit is owner, that is to say that the site Steemit can be sold, but this will not affect in any way the information that is in the blockchain Steem.
Imagine that way;
When the bank's bank is broken, you will not get access to your money using that cash specifically, but your money remains in the bank the same way. You can access it by other means (like using another ATM that is working for example). The same thing happens with the Steemit site regarding the Steem blockchain
Steem and Steemit were created by the same people Dan Larimer and Ned Scott. Although they are creators, even selling the site Steemit in the future Dan and Ned will not have any kind of direct control over the information that are blockchain Steem. Any information stored in the Steem blockchain will be there forever no matter what happens to the site. The site is only meant to interact with the blockchain. That's why we say that the information in the blockchain is censor-proof.
In the near future we will see numerous applications and sites in general interacting with the blockchain Steem, in fact they are already appearing. Tools like Steemstats were created by third parties and many others will come with certainty.
If you are a programmer you can even create an application that uses the information contained in the blockchain Steem. It would be possible to say that another site can even take the place of Steemit as the main tool to access the Steem blockchain, this would be totally possible if the community wants to.
I approach this issue carefully because I believe this is the greatest fear of the people who start at Steemit. I would say that it is very likely that numerous competitors will appear regarding the Steemit site using the same information that is contained in the Stech blockchain being this very interesting indeed.
So rest assured if for some technical reason the Steemit website goes out of the air, the information that is in the Steem blockchain will continue there in the same way and can be accessed by another site or application. I say that because Steemit is in beta for now and that may mean it's out of the air for a few minutes every now and then.