I think everyone at this point knows Slack. It is a messaging app for businesses. Recently sold for $28 billion to Salesforce.
So why is it so successful? Well I had seen someone suggest it was word-of-mouth, or that they listened to their customers and not some big marketing budget... Although I did see on Yahoo Finance they quoted SEC filing that showed Slack spent 50% of its revenue on Sales & Marketing. So we are talking millions.
Now why does this matter to you. There are a number of benefits but the main two are:
Time, you don’t have to build out another feature or reinvent something that already exists.
Money, they already spent to advertise and reach a lot of people. You can piggy back that most of the time for free.
This is why it is important to integrate with services that make your product stronger and not waste time trying to compete