http://www.adobe.com/type/browser/info/embedding.html
"Preview & Print: A font with an embedding permission of Preview & Print allows the font, either fully or as a subset, to be embedded in an electronic document solely for the purpose of viewing that document on screen and/or printing that document. While a font with a Preview & Print embedding permission (either through data in the font file or the font’s license agreement) may be embedded in an electronic document, the embedded font may not be used to further edit the document it is contained in or to edit or create other documents. Most fonts in the Adobe Type Library are set for Preview & Print embedding."