<p>Zulily, a mom-focused website specializing in offering discounts that expire after a limited time, last week filed its papers to go public. The section in which it discusses risks to its business includes one very specific development its concerned about: the new Gmail.</p><p>Google (GOOG) recently altered its e-mail service to help users sift the in-box wheat from the chaff. The company now separates e-mails into different tabs, potentially banishing e-commerce messages into a tab that's less likely to be checked regularly. That's nice for Gmail usersand not great if you run a company based on sending digital refuse to thousands of customers.</p><p>The problem has other companies nervous as well: Gilt Groupe and Groupon (GRPN), for instance, have been telling customers how to get their messages to show up among the e-mails of higher importance as ranked by Gmail. It could be particularly bad for flash-sale sites, since a promotion could expire before a user gets around to checking out their least-used tabs.</p><p>Zulily gets three-quarters of its Web traffic from e-mails or other forms of unpaid advertising. But it warns that other e-mail providers or social media services could follow suit, or that the kind of messages it sends could at some point be caught up in anti-spam legislation.</p><p><a href="http://www.businessweek.com/articles/2013-10-14/how-your-newly-uncluttered-inbox-could-doom-zulilys-ipo">Keep reading...</a></p>