From that Lassa is surmising that the GM has possibly decided not to brand the Volt as a Chevrolet but instead sell it under a premium brand like Cadillac. The rationale for such a move is that production cost of the Volt is high enough that calling it a Cadillac would allow GM to charge a higher price and hence recover more of that cost. While this seems reasonable, it also seems highly improbable.
When GM announced the Volt they made it clear that unlike the GM branded EV1, they were calling the Volt a Chevrolet because they wanted the car to be a high-volume, mainstream model. They know full-well that they will almost certainly take a loss on the Volt in the first couple of years. Bob Lutz has made clear that they intend to sell the Volt for well under $30,000 and GM has already started running TV ads and billboards that feature the Chevrolet branding in conjunction with the Volt. Most likely the lack of branding on the list for both the Volt and the Global Delta MPV7 (the next generation Opel Zafira) is due to the fact that both vehicles will be sold globally under different brands in different regions. Here in the US, the Volt will almost certainly be a Chevrolet.
[Source: Motor Trend Blog]