I applied for a job at a staffing agency, and they said they'd let me know by email--is that (already) a bad sign?

A lot of jobs honestly nowadays are contacting you by emails. Past couple of jobs in the healthcare informed me by email first then phone. I would just call if it's been a while since you heard back and check the status of your application. If it's something you want dont give up. Keep applying and trying and something will come along. Good luck!!!

Yes. Trust me, in the past year I have been dealing with countless staffing agencies and they fucking suck. Not even worth working for one.

If your number isn't in his phone, Siri wouldn't know how to call you. Email is how it's done these days.

You might hear from them but I doubt it

... what's a truck driving job doing at a staffing agency? 🙄