Specifically the talk titled "Unicode Support Shootout: The Good, The Bad, & the (mostly) Ugly"
It's a year old now, but it's still relevant. It gives a very detailed look at unicode support across JavaScript, PHP, Go, Ruby, Python, Java, and Perl.
Tom Christiansen's talk Unicode: The good, the bad, & the (mostly) ugly covers a lot of Unicode wrinkles and how Javascript, PHP, Go, Python, Ruby, Java, and Perl handles them.
I think that depends heavily on what programming language and frameworks you are using.