I entered a giveaway for a chance to win an Amazon gift card on Zanetti’s website and was directed to Writerspace. According to their “About Us”:
Writerspace currently hosts, maintains and promotes sites for over 100 individual authors, including many New York Times bestsellers, and we promote over 500 authors via our individual, group and publisher sites.
There are giveaways (signed copies, ARCs, gift cards, etc) for different authors with links to sign up.
Good luck! :)