Just how much of your Web behavior is actually tracked by data aggregators? Well, Google and its affiliates alone track visitor identities on nearly two-thirds (64.4%) of worldwide Web browsing, according to a study by anti-tracking vendor Ghostery. Facebook trailed with trackers for a mere 28.8% of all page visits. Ghostery found 77.4% of pages had at least one tracker while more than 15% of pages had ten or more.

Here’s an alliance between data vendors. Time Inc.-owned Viant, which has an advertising audience database of 1.2 billion registered users, is adding information from retail data aggregator IRI. Marketers will get a clearer picture of advertising results at fine levels of detail, although not tied to identified individuals.

Just over one-third of marketers plan to either buy a new CDP (21%) or replace an existing one (13%) this year, according to this Optimove survey. Unfortunately, it doesn’t report how many have a CDP already in place, which would put the other values in perspective. It does seem that CDPs are a relatively low priority: they rank sixth on the list of new systems and eighth on the list of systems to replace.