You’ll need to be comfortable with using the command line, but this is a very useful font subsetting tool from those clever folks at Filament Group.
Domains registered with punycode names (and then given TLS certificates) are worryingly indistinguishable from their ASCII counterparts.
Can you spot the difference between the URLs https://adactio.com and https://аdаctіо.com?
Glenn Fleishman on the war of attrition between primes and quotation marks on the web.
Some excellent research for web developers: find out which unicode characters have the widest support—release useful for choosing icons.
This is a great free service for generating small subsetted icon fonts. Launch the app and have a play around — you can choose from the icons provided or you can import your own SVG shapes.
Nice touch: you can get the resulting font (mapped to your choice of unicode characters) base-64 encoded for your stylesheet.
Stuart posts a really handy string for testing internationalisation: Iñtërnâtiônàlizætiøn