I love the idea. I'll likely be using the site soon for some small sites I run but don't make enough money or traffic to warrant the "heavier" choices for support pages.
One thing you might want to add to encourage people to sign up is allow contact form submissions to be pushed to the slack API for paying users.
One thing you might want to add to encourage people to sign up is allow contact form submissions to be pushed to the slack API for paying users.