They have more integrations than are showing on the home page, but the only way to see the full list is to sign up. I uploaded some screen shots showing the available services/integrations: http://imgur.com/a/NR7Af
Dev B: "What about Skype? It's one of our products."
Dev A: "I don't care, I only use Slack. Screw our users, right?"
Dev B: "What about Skype for Business? People actually pay for that."
Dev A: "Nah, Wunderlist is much more important. Much."