I haven't read Pariser's book, so apologies if he addresses this perhaps obvious question, but what exactly are today's "filter bubbles" being compared unfavour

I haven't read Pariser's book, so apologies if he addresses this perhaps obvious question, but what exactly are today's "filter bubbles" being compared unfavourably to? If it's pre-internet, the situation was surely worse: not only was the overall level of access lower, and the range of information much narrower, but the majority of it was likely largely being fed by relatively traditionalist media institutions. Anything of any diversity would have to be proactively seeked out by interested, curious individuals, and even that stood a good chance of coming through an echo-chamber-ish filter bubble of like-minded friends or narrow-issue sub-cultures? If on the other hand contemporary filter bubbles are being compared to early days of the UK internet, there simply wasn't as much adoption of or engagement with the web then, so the above still applies for most of the population.