VYPER is an email marketing tool that allows you to create stunning giveaways that help you collect emails. Once a user enters your contest with their email address, they're incentivized to share your contest (via email or social media) in order to get more entries. This viral loop allows you to quickly add new emails as well as increase social sharing and followers.
We also have several features that help make your contest a success, including prizes that get awarded for every contestant (called bonuses or opt-in bribes), cheating detection, and integrations with popular email service providers like Mailchimp.
via BetaList http://bitly.com/1YHMJca
by Robert Hughey (Google+)