AdRoll's SendRoll feature announement
AdRoll is a retargeting and prospecting advertisement platform for businesses. They use a combination of modal windows and tooltips to frequently release new features to existing users. Here's how they use modal windows:
What we like: these modal windows are brief and informative, and consistent with the rest of the product design-wise. Plus, with a transparent background, these modal windows allow users to keep an eye on their end goal while they read about the new feature.