One of the most important aspects of routers is that unlike consumers' computers, they tend to be left on. As such, this change will significantly increase the quantity of always-on, always connected computers in the retail market.
This increase will be of immense benefit to distributed computing projects such as Folding@home, but will also provide the opportunity for open-source, community-driven, cloud-like services to arise: distributed versions of all of the online services we currently see today. The Diaspora Project is an early example of this, but for most, if not all online services, there is an opportunity for a distributed, community-controlled alternative.
The benefit to telecoms companies (why it might be adopted)
As IPTV takes off, significant strain will be placed on the network. By placing storage into customers' homes, telecoms companies can take advantage of troughs in traffic to cache popular content locally, helping to ensure both good customer service and network resilience.