If you're one of the folks who is testing out (or using the now released) new Firefox then you've probably seen an error message saying something like "Security Error: Domain Name Mismatch" and then it says a bunch of jargony stuff and then you see that the domain is for "sb-ssl.google.com error 12263... however the security certificate presented belongs to www.google.com...If you suspect the certificate shown does not belong to sb-ssl.google.com please cancel the connection and notify the site administrator". What the heck is that?
What is sb-ssl.google.com
Well, as this page in the Mozillazine Knowledge base will tell you it's about a secure browsing preference.
This is the Google Safe Browsing extension, installed by default in Firefox2.0, which lets you know if you've hit upon a nasty page.
It could also be used to collect information about your "click stream" so that Google knows where you've been and can then serve more contextually relevant ads to you.
Really though, the most annoying thing in my mind is that Google doesn't have a valid certificate for that domain which means that all users get some crappy warning on each load of Firefox.
Other Providers, like Lijit
Personally, I think the model of lijit is a slightly better one but both never hurt. It would be nice if there were other advertised providers of the sb-ssl.google.com web service so that Lijit could also provide that information. There probably is a way to do that which would just require changes to the Lijit infrastructure - hopefully they'll get there.