Comment by lmm

Yeah, it looks like the font is scaled slightly wrong along the x-axis, so that the displayed pixels don't quite line up with screen pixels. Specifically, the text is rendered about 0.5% too narrow, causing a moire-type pattern that repeats about every 200 pixels.

Adding this custom CSS rule seems to fix it for me:

    p { transform: scale(1.005, 1); }

Same here, I think it's caused by the font it's using (BitGeneva12 [1], which obviously is a geneva [2] clone but I can't find where it (the font) is from. Maybe the author created it themselves?).

[1]

    src: url(//www.hypertalking.com/wp-content/themes/hypertalking/fonts/bitgeneva12-webfont.eot);
    src: url(//www.hypertalking.com/wp-content/themes/hypertalking/fonts/bitgeneva12-webfont.eot?iefix) format('eot'),url(//www.hypertalking.com/wp-content/themes/hypertalking/fonts/bitgeneva12-webfont.woff) format('woff'),url(//www.hypertalking.com/wp-content/themes/hypertalking/fonts/bitgeneva12-webfont.ttf) format('truetype'),url(//www.hypertalking.com/wp-content/themes/hypertalking/fonts/bitgeneva12-webfont.svg#webfontx0MbJbLm) format('svg');

[2] https://en.wikipedia.org/wiki/Geneva_(typeface)

This seems to be because Firefox has no way to disable text antialiasing (whereas Safari and Chrome support -webkit-font-smoothing), so Firefox is trying to antialias a pixel font which just looks weird

Same here. Also a more minor issue for people like myself, the site causes some 'glare'(?) and is difficult to look at.

I've had this issue since my childhood, now that I think of it. On paper (especially grids) and websites. I should probably figure out what it is.