What the author doesn't realize is he's doubled nothing. DOCCIS networks are shared mediums. That means you have to double bandwidth by increasing the number of channels you have. Newer DOCCIS modema are already bonding channels today. Most commonly 4 channel bond on the downstream and 2 on the up. By connecting to the cable modem twice, via two different routes, does nothing to change the available bandwidth available to the users behind the CPE (cable modem). As some have stated you could do this against your neighbors modem to share more channels on the cable media, however your neighbor is on the same HFC node and sharing the same available bandwidth to how many other users are connected to that node. You may get a few extra megabit but its the latency that will make that portion of the link "slower" so you really won't improve things much, if at all.
The best way to improve consumer Internet connection is to get a fast router that can route fast in hardware. I'm always amazed people think a SOHO device doing WiFi, NAT, DHCP, DNS, etc. on gimped hardware is "fast". The majority of time it's not and real improvements can be realized with dedicates hardware. Meaning that until you split service off from routing using cheap, consumer SOHO gear, will most always be the bottleneck.
