Asana vs Slack

Asana is the shared task list for your team, where you can plan, organize & stay in sync on everything.As fast as a text editor. Plenty of keyboard shortcuts, fewer page loads and mouse clicks. Asana is one app that won't get in your way. Free Asana alternatives are Bitrix24, Producteev, Remember The Milk. Asana open-source self-hosted alternatives are: RedMine and ProjectPier.
Slack brings all your communication together in one place. It's real-time messaging, archiving and search for modern teams. Create open channels for the projects, groups and topics that the whole team shares. Slack searches whole conversations, not just individual messages, so you can find what you’re looking for no matter who said what or when they said it. Slack free open-source (self-hosted) alternatives are: Mattermost, Rocket.Chat, Zulip
Asana has better video than Slack

2014 - Asana finally launches iOS app. Slack keeps calm

Popular collaboration service to corporations and groups Asana released a unified iOS application for iPhone and iPad. It provides normal Asana features like task management, search, and calendar capabilities. It also includes a green-colored button that allows quick task making, or taking a note. The app itself sports what the firm called a new “design language” that is more vibrant than what preceded it. That language will, over time, leak into Asana’s web product. In its current form it contains small effects like a heart-based animation and colorful tags. The similar Android app is under construction now.