Let's say you're streaming data at 5 Gbps (probably the size of Sonic.net's network) on average. That's 1.62 PB of data per month. To cope with the speed at which data is being collected, they'll need to have a rack of Backblaze Pods (cheapest storage system out there) running, at a cost of a few hundred thousand dollars.
Of course, URL logs may be a bit smaller. Maybe one Pod (135TB) gets used per month (remember, lots of AJAX stuff going on). That's still thousands of dollars per month that could be used to add a few more fiber customers, or to add another gigabit or two of network transit...