Having read Molly Ostrander's question, it is clear that a request for permission to include an item in a course pack will not automatically extend a right to mount the same material in an electronic reserves database. One must be explicit when asking permission for different types of uses. There may be some fair use rights in this case, and that should have been explored before the subject of permissions came up in the first place. The confusion here comes from looking at the two types of uses as parallel, which some in the publishing community like to do. It is important to keep course packs and electronic reserves distinct in our minds.
Course packs are ordinarily saleable items.
A copyright clearance fee is included in the purchase price. For electronic reserves, the system may be populated with items for which fair use has been claimed, or for which permissions fees have been paid- or some combination of both. The only time I can think of when it is useful to group these two distinct services together is when negotiating licenses for full-text databases. In that case, you may want to ask that your license fee cover use of materials in either course pack or electronic reserve form, or both.