AdRoll's targeted integration announcement

The ad platform AdRoll helps companies place and monitor ad campaigns around the web (Facebook, Twitter, Instagram,  Google) from one easy, convenient place. AdRoll uses modal windows to announce important feature updates inside their product.

Why this is really good UX:

• The announcement offers a high-value add to customers who already use MailChimp. For them, the full-screen modal is a welcome messenger, not a workflow interrupter, that helps them improve how they use the tool.
• With targeted notifications, users who don't use MailChimp, and who'd find the interruption annoying, didn't receive the modal. Instead, they continued their work happy and undisturbed.