What counts as traction?

Wouldn't Traction be Revenue / sales. Daily users if they were increasing.

I think Going viral and Press coverage are vanity metrics. It's the revenue and increasing users that shows traction.

Depends on the business model. I would go for revenue/sales from the first day. But for some businesses, getting users initially for future revenues may count as traction

Depends on the level of viral and press coverage, but usually, these things bring a lot of users that don't stick. I would say having daily users proves to other potential users that your product is something of value and will attract them as well. Of course, I'm speaking more from my common sense since I don't have a lot of hands-on experience with the above.