Thanks! Android is planned. You add someone by searching their name, clicking their link, or using Nearby which shows people who have the app open near you using Bluetooth.

> 100 contacts limit seems really low

I think after connecting to people 100 times you'll feel like paying one cup of coffee a month is worth the value you get out of the app.

> For vanity url usernames, I'm not sure if this works or just fragments namespaces more.

Not quite sure what you mean, but usernames are primarily intended so you can put a pretty, memorable link in the bio of your social accounts or on your business card.

If Cardbox becomes the initial point of digital connection, then here's where a good username will matter most; your other accounts are easily found anyway as they're linked on your card.

Making usernames work like domain registrations also solves the problem of usernames being squatted, or taken and abandoned. It's also an incentive to keep paying. I believe it's a good solution :)