Chocolate Factory still stomping bugs out of its bird-themed post-third-party-cookie features Share Copy Updated Google's effort at "building a privacy-first future for web advertising" already looks like it will require some privacy retrofitting. The internet titan's interest-based ad-targeting technology, Federated Learning of Cohorts (FLoC), ostensibly intended to provide a more privacy-friendly alternative to third-party tracking cookies, has a privacy flaw, according to Dr Lukasz Olejnik, an independent privacy researcher and consultant. "Unfortunately, it seems that FLoC contains a privacy design bug that leaks the information about whether the user is browsing in private mode (Incognito) or not," Olejnik wrote in a blog post on Monday, noting that he'd spotted a similar Incognito detection bug in another API.