Lots of sites need to know your age these days, either to customize your social-media experience, validate legality, or just to send you those annoying birthday greetings.
Since all these websites know everyone's birthday, maybe they should institute age-specific font-sizes. So it'd be the normal font for those under 30. One size up for 30-45, two sizes up for 45-60, three sizes for 60-75, and a special large-type edition for surfers over 75 years of age. This could be easily accomplished technically by serving up special CSS stylesheets based on the age of the reader.