It's a valid concern and I've certainly seen communities fizzle out (even my own). In a large part it's up to us! Keep posting, keep replying. If you post something elsewhere, maybe remember to copy it here too.
Perhaps Webwide could have an API / webhook / easy programatic way of cross-posting to assist with that.
@Adam has mentioned moderators, if himself and mods take on a bit of a community lead roll that'll go a long way. A good example already is the
community challenge that's running.
He'll also likely have to keep promoting Webwide on other channels like Twitter (which is already happening).
You could add some scripts down the line to automate some social posts, aka when a thread gets over say 20 posts automatically Tweet it, etc.
RE not being a forum. I don't know. Other communities like StackOverflow, Dribbble and Twitter already exist, so copying them would be fruitless. Forums have gone out of popularity but perhaps that leaves a bit of a hole in the market for a new, modern forum. There are certainly people who miss the community feeling and hijinks of forums. Adam has chosen a modern forum engine and gone some way to customising it, I'm sure there's more that can be done.
I saw someone ask why not Discourse, I haven't really used a Discourse board but they seem better suited for product help and support than a community. I guess it feels more utilitarian, though that's not to say it couldn't be customised also.
For now I guess, keep hyping! 🎉