When launching a contest, the client can choose between a public, semi-private or private contest:
A public contest can be seen by everyone. The description of the contest and the creations are public.
Visitors to a semi-private contest must log in to view the contest. This implies that instructions and submissions are protected against search engines like Google.
In a private contest, the instructions are visible to the connected visitors, but the designs are only visible to the client. With this option, designs are also protected against search engines. This is the best option if discretion is required.