Technologies: PHP, C
Between my (now retired) Mobile Safari handwriting recognition site, iFone Chinese, and the assortment of random tools online, surfing the Chinese internet is not only a mental exercise but also an excercise in alt-tabbing between different translation tools.
One weekend at Microsoft Research Asia, I was gearing up for a heavy weekend of coding. Alas, apparently a pipe broke in the data-center (apparently?) and all the servers I needed were taken offline. I had to put my pent up momentum into something and so I decided to create a bookmarklet that could annotate chinese characters on any domain with their pronunciation, and Add Pinyin was born (it was actually originally called Pinyinify).
The idea is that on a Chinese page you click a bookmarklet and the pronunciations are added alongside each character. Try clicking here and watching the text below
Add Pinyin has two possible underlying engines - a PHP engine that references a memory-mapped file and a C server that serves requests asynchronously from an in memory dictionary. The C server can serve around 10,000 requests per second, but (obviously) required more maintenance than a stateless PHP script. At the moment, the C server is tucked away until traffic spikes.