Whilst these products are in their infancy the underlying engine is quite grown up, so don’t let the ease with which these apps get up and running fool you into thinking that they are just light weight solutions. The scanning engine has been tested by scanning large chunks of the internet from a lap top over wireless via a 10/100 network and a very poor broadband connection ie a worst case scenario.
We have scanned over a million IP address in a single scan on a number of occasions. They will scan highly fragmented global networks with numerous sites in many countries, in a single scan. They traverse global networks, utilise routing and will find every IP address in the supplied range, providing that there is a route to it.
They bypass local windows firewalls so even boxes that are effectively hiding will be found.
You can quite literaly scan the entire internet using ScanITDiscovery (at 250 nodes per second), the other products will scan the internet but rely on domain admin rights of the user to access/probe boxes, as the internet is not a Windows domain it cannot be probed in this way. However it can be discovered and ScanITDiscovery will return IP Address, HostName and MAC provided that your connection to the Internet is appropriatly configured.
A word of warning should you be inclined to attempt this, ie scan the internet, your activities may cause panic at your ISP because the behaviour of this app, at TCP/IP level, would give the appearance, to packet sniffers, of a bot net or DOS,DDOS attack due to the rapid processing of IP Addresses.