The two are definitely related, but they are separate. Steemit.com is currently the main website that users can use to interact with the Steem blockchain. The actual website (Steemit.com) is owned by Steemit, Inc. When you get SP/STEEM/SBD, you are getting tokens which give you a stake in the blockchain, as defined by the blockchain rules. There is no ownership of Steemit, Inc or the Steemit website though.
[Edit] Currently, Steemit is one of the main things that is providing value to the blockchain and making the currencies worth something though.
So in a sense we all do have a share? I understand that the tokens are separate but it's like one supports the other. Anyway I do get what you mean but from a point of view, we do have a "share" in the platform.
Yes. We do have a share in the Steem blockchain platform. If the Steemit.com website makes the Steem blockchain platform a success - then we are all shareholders of that :) The distinction is what we are a shareholder of though. Even if Steemit.com becomes the #1 website in the world, we would be shareholders of an extremely popular and heavily used blockchain, but we still would not have ownership in the actual website.