The release of the BSP that runs on the Intel® Atom™ Processor E660 with Intel Platform Controller Hub EG20T Development Kit comes in two flavors: full open source and a EULA version, which is an open source version with some binary components for which the source is not available. The full open source version uses generic vesa support and is fully open to the community. The EULA version uses the proprietary Intel Embedded Media and Graphics Drivers v1.5, which take full advantage of the hardware for better graphics performance as compared to the open source version.
You will notice that the EULA version of the BSP requires that you sign an End-user License Agreement (EULA) in order to download the tarball. Why is a EULA necessary? What am I signing here? These are valid questions. Any time there is proprietary code for which you cannot get the source code a EULA will be involved as part of the download process. So, signing of the EULA depends on whether you are going after the BSP that takes full advantage of the EMGD driver or if you can get by with the full open source solution.