Sign up with a goal
UserVoice did something amazing in their sign up process, and it is so simple to implement. They asked why I'm signing up.
One thing that annoys me is when you sign up to test something out. Days later you get bombarded with emails asking you how your project or campaign or what have you is doing. I just wanted to see what the features are like!
Having something at sign up at asks a user's motivation not only takes care of that pet peeve (hopefully this means the follow up emails will be more helpful to my goal), but it also shows that they care about why I'm interested, and not just trying to get another user (we hope).
Last, it helps create a customized experience for users. Coming from the 3D printing industry, I am all about customizations. Recently, I've seen more and more customized UX experience on the web side as well. Different content show up for whether you are beginner or advanced, logged out vs new user.. and my favorite, I got a weather specific email based on my location (it's rainy today, why don't you order your dinner from...). Creepy? Maybe for some. For me, it put a smile on my face and made me feel just a little bit more special. When your users are using "feel special" you know you are on to something.