How do callbacks to vbseo.com or crawability work exactly?

From another post, I gather that everytime a page is loaded vBSEO calls back to vbseo.com or crawability.com to verify the license?

1. Does this cause all your pages to load just a bit slower because of this extra call to the external licensing server?
2. What happens in the case of a network outage between your server and vBSEO's server?
3. Are the vbSEO licensing servers redundant and on different networks to prevent downtime if one licensing server or its datacenter or some element of its network goes down or encounters a slowdown?

This is incorrect.

During installation, vBSEO will retrieve your license key only 1 time. Once it is stored in your configuration, it will not be retrieved again until you upgrade to a new version.

OK, excellent. Sorry for being concerned about nothing. I saw in one thread the mention that "your site will show not licensed" when someone asked if they could install directly after purchasing a second license but without waiting a few hours for approval of a second site and I thought that meant it would show all over and not just not allow the install. My bad.

(and glad to hear that it doesn't require constant callbacks; a couple times when vbulletin.com went down or was experiencing problems I found the few second delay in my admin CP an annoyance, so I figured if there was a non-mission-critical-redundant callback that could affect all forum pages that would be a dealbreaker, as well as any slowdown caused by all those extra connects)

Originally Posted by Island

OK, excellent. Sorry for being concerned about nothing. I saw in one thread the mention that "your site will show not licensed" when someone asked if they could install directly after purchasing a second license but without waiting a few hours for approval of a second site and I thought that meant it would show all over and not just not allow the install. My bad.

It will show (Unregistered) beside the vBSEO copyright at the bottom, and URL rewrites will not work. Once the new order has been processed, it will go away and vBSEO will start "working". There is really no reason to install vBSEO to one of your additional sites until your order has been processed.

That's no issue as long as it's just a one-time callback -- I was worried that if for some reason the vBSEO server/network went down at some point in the future for whatever reason (as we saw happen to vbulletin.com once or twice in the past years) that there would be a continuous callback that would be triggered to cause vBSEO to stop functioning -- that would scare me and be undesirable.