How does Meraki work?

Meraki is evidently some sort of combined wireless router and ad-supported public wifi provider. The website doesn’t explain how it works very well, though. From what I can gather, it seems that in the standard/normal one-device residential deployment, you plug a Meraki device into your cable modem, and it provides wireless access to the internet. The difference between this a regular wireless router is that it offers two sorts of connections: (a) a WPA password protected connection that works pretty much exactly the same as a wireless router; and (b) a public (throttled) connection, open to anyone, that delivers ads. (You can disable (b).)

Another significant difference is that instead of configuring it via connecting to a webserver built into the device itself, you use an admin area on meraki.com. So, by design, it “phones home”. I can’t figure out how often it connects, or what information it sends and receives. (It must be getting the ads from meraki.com.)

It looks like the ads are served by rewriting HTML–is this correct? And if so, are all other ports untouched? Do https pages work?

The Meraki also supports some wifi mesh system, whereby you can essentially connect a whole bunch of Meraki devices to power and the internet (at least one needs an internet connection), and it will create one big wifi network and figure out how to route traffic from one device to another and finally out onto the internet. But I’m not so interested in this bit.

uPNP isn’t supported and port forwarding is difficult (maybe impossible on the smallest Meraki).

The Meraki business model seems to be somewhat similar to that of fon–how do they compare?