That's correct. There will be no centralized website. You will have to run a Synereo node to take part in the network. The plan is to make running a Synereo node as easy as downloading, installing, and running an app. You log in to your account via the app.
Is this definitely the way it will work - you will have to download and install an app to be on the Social Network? I assumed various individuals could host their own nodes and you could register there. Having to download/install something to get connected seems like a fairly large barrier to entry