When a visitor of UrbanDictionary has not found the term he was looking for, he is redirected to a ‘Why you don’t write this definition?’ screen. Clever idea not only to get user-generated-content, but also more signups (if the user wants to save his definition, he will have to signup).
BuilWith gets signups by offering up to 20 results for free. If you don’t know about BuiltWith, it’s a tool that allows you to know what techonologies, tools, frameworks or platforms are using others websites. Their main business model is ‘pay us for having the full list of companies with XZY technologies’. They offer the 20 first results for free, after that, they ask for your paid signup.
Buffer provides a WordPress plugin (digg digg) to make it super-easy the way of sharing content of your blog. Even if it’s not their core business the development of WP plugins, they know their vast majority of their users might be using WP as platform to blog, so why not to make the path easier
Uber did it again. If in summer, they used their app to deliver ice-cream-on-demand, last weekend they tried to activate users delivering christmas-trees-on-demand.
Once you add the KimonoLabs add-on to your browser, it shows a figure with the number of current APIs created by other users in the page you are currently browsing.
Betabrand knows how important can be to have as many data as possible of a potential customer. When they invite to you signup for future offers, they give you two options: either get a 10% discount in your next purchase if you just enter your email, or get a 20% OFF if you sign-up with your Facebook account instead.