Outdated in what sense?
> I get a lot of email, and messages from family and friends might not get seen for 6 hours (or more).
Why doesn't it get seen for 6 hours?
> The better comparison here is a text message, but they can still get lost in the noise too.
How are you reducing the noise? Imagine now, I have an e-mail client, a SMS client, a todo app, a txt app, 10 gaming apps that all have notifications for me to "do something", how is the issue being solved? My noise is still the same, all I've done is created (yet) another beacon for displaying signals.
ps - Hopefully, I'm not detracting you from your hard work. Trying to provide some honest feedback here that I'm hoping will help you.