Tracking stuff came as soon as you could communicate asynchronously with a server, really. It became widely known and a plague in the 10s but it started as soon as Ajax was available. Keep in mind that Google and most of the websites were free and ads driven almost from the start because that was the only way to create a critical mass of users.
You could definitely track folks with cookies well before Web 2.0, but the storage and processors necessary for the sort of data harvesting we see today didn't really get profitable until the '10s. Before that Google would run ads that were relevant to the search query rather than tracking your move around the web.
Tracking stuff came as soon as you could communicate asynchronously with a server, really. It became widely known and a plague in the 10s but it started as soon as Ajax was available. Keep in mind that Google and most of the websites were free and ads driven almost from the start because that was the only way to create a critical mass of users.
You could definitely track folks with cookies well before Web 2.0, but the storage and processors necessary for the sort of data harvesting we see today didn't really get profitable until the '10s. Before that Google would run ads that were relevant to the search query rather than tracking your move around the web.