I have a lot of similar thoughts about Slack and also had the idea to go head to head with it a couple of years ago. I partnered with a PHD researcher who had expertise in the area of focus.
Before I started building I launched a paid sales campaign to see if people would be interested with a mocked up website looking like we already had the product. I had a lot of website visitors, but nobody signed up for a demo. Not one person. At that point I realized that whether or not the product was a good idea, I didn't know how to sell it, so I ditched the idea, deleted the test website and moved on.
Before I started building I launched a paid sales campaign to see if people would be interested with a mocked up website looking like we already had the product. I had a lot of website visitors, but nobody signed up for a demo. Not one person. At that point I realized that whether or not the product was a good idea, I didn't know how to sell it, so I ditched the idea, deleted the test website and moved on.