For whatever it's worth, the user that posted this link (onebookaday) appears to be a dedicated account for posting links to Boox products; active 7 months, 4 submissions, 5 comments, all surrounding the release and promotion of Boox products. I don't think it's expressly against HN guidelines ("Who's hiring" posts obviously have corporate accounts post), but it does seem a little disingenuous for the account not to disclose that information in either their comments or the profile's "About" information.