What is NSDL’s purpose? Here’s the official answer: “providing organized access to high-quality resources, materials, products, and services that support teaching, learning, and research at all levels of science, technology, engineering, and mathematics (STEM).” Which digital resources are appropriate for NSDL’s collection, and which are not? Who owns these materials, who is responsible for their upkeep, and who decides whether or not something stays in or is thrown out? Answers to these and many other questions are in the NSDL’s new Collection Development policy. The document describes NSDL’s mission; the communities it serves; resource ownership, management, and description; the scope of collections; quality guidelines; responsibility for selection, accessioning and de-accessioning collections; and terms of participation. The new policy and the Contribute Resources and Collections page on nsdl.org are especially helpful for resource and collection developers, providing official answers to many basic “what” and “how” questions about NSDL and contribution to the library. You can download the document at our blog and leave your reactions at the blog Community Comment to NSDL Policy Drafts. A revised Privacy Policy is in the final stages of review and will be released soon.