The COPPA Rule requires website and online service operators to give notice to parents and obtain verifiable parental consent before collecting children’s “personal information” online. 16 CFR §§ 312.4, 312.5. The definition of “personal information” encompasses some obvious pieces of data – name and address, for example – and some less-obvious ones, such as screen names, geolocation data, and “persistent identifiers.” A “persistent identifier” is a piece of information “that can be used to recognize a user over time and across different web sites or online services,” such as “a cookie,… More