Nvidia has decided to drop the “Designed by Nvidia” moniker for motherboards, originally intended to simplify product manufacturing and make it easier to get products to market. While the goals may have been simplification and standardization, it seems the tag was more confusing than Nvidia expected. As a result, they'll instead focus just on motherboard and GPU standardization, ending the existing program:

However, many makers were confused by the scheme, and therefore Nvidia has decided to stop using it, but the strategy of pushing standardized motherboard and graphics cards will continue.
The Designed by Nvidia program is used by many companies currently, such as eVGA, BFG, XFX and others. This will probably not impact their product lines at all, so really this is nothing more than a label going away. Nvidia will still obviously push for particular chipsets to be coupled with particular GPUs.