What are the specs of vpsBoard server?

[eva2000]

You can handle many millions of visitors a day on such servers.  Depends though on the app/middleware layer and caching.

86400 seconds in a day.

1 million users divided evenly is 11-12 new user requests every second.

Exactly. It isn't how many visitors/day you can handle that really matter, it's the peak user concurrency load you can handle for a given server/ram spec'd size

10,000 users spread out evenly over 24hrs = 0.12 users/second 

vs

10,000 concurrent users at same time

Doubt the latter scenario would survive on a 256MB Nginx server

But nice to know what powers vpsboards