So here am I, average Internet consumer sitting and sipping coffee, doing nothing but wondering why my fonts look so much better almost everywhere I look.
I still vaguely remember those disgusting, misaligned, aliased Linux fonts of the 2000s. What the heck happened since then? I certainly didn’t do much about it. Well, maybe tweaked a setting or two, but nothing major.
Are we using newer fonts, are we smarter about font choice or are the same old fonts appearing better on LCD screens because rendering, hinting and anti-aliasing algorithms work so much better?
This question seems more oriented towards technology than graphic design per se, but as other commenters have noted, technology has improved – namely screens got better and could display more pixels in a given area (hardware) and that rendering and hinting algorithms got better (software). Another possible reason for improved font rendering would be the rise of LCDs over CRTs – we no longer need to deal with painfully slow refresh rates.
Moving beyond your original question about font rendering, perhaps the biggest breakthrough for fonts and graphic design in the last 10 years would be the successful inclusion and implementation of web fonts. Websites can now utilize rich typographic features that were previously impossible.