Old Internet was where the primary content was content.
Ads appeared as a curiosity in 1994 but didn't start taking over until around '96, which is when the ad networks started to become more industrialised with tracking and ROI metrics (of a sort).
New Internet is where the primary content is ads and behaviour mod. Virtually all big-reach content is only there to make the ads and behaviour mod work.
And of course the goal of Meta is to personalise ad delivery even further and make it even more intrusive and impossible to ignore.
This isn't just a technical difference. There's a huge difference in culture and motivation. Old Internet was about exploration, play, and sometimes debate. New Internet is about exploitation, driven by psychological and emotional manipulation.
New internet is where any useful information about said product gets buried in marketplaces and producer pages, following half a dozen paid-for ads.