Are sales of e-books subject to sales tax?

According to the NYS Tax Department, apparently not [PDF].

"...e-books are not tangible and do not include any prewritten computer software. Accordingly, they do not constitute tangible personal property. As to whether the e-books constitute taxable information services, TSB-M-11(5)S provides that the Tax Department's current position is that electronic publications that meet the memorandum’s definition of an e-book do not constitute information services."