To make good on its ballooning multibillion-dollar valuation, online-messaging service Twitter Inc. must pass the Sephora test. Initially, Sephora, the makeup retailer that is part of luxury-brand-giant LVMH, didn’t allocate any funds for Twitter’s young advertising system for this year. But in February, it bought more than 15 Twitter ads to promote a contest for …

You must be logged in to post a comment.