Slack being a unified communication tool allows syncing your chat with desktop, i Phone/i Pad or Android device. Slack makes it dead simple to find older links or messages that someone sent a few weeks ago.
Not only it is super fast and friendly to search, but it is also filterable.
Download Slack: Android | i OS Business Chat- When it comes to instant messaging and video chatting, Skype is one of the first few apps that comes to mind a few years back.
Skype had managed to build itself a huge user base even before Microsoft bought it in 2011, and its user base has continued to increase ever since.
Instead of using a username or email ID, you can create Whats App account with a phone number.