For anyone who is learning Chinese, this add-on is a must have…I used to spent a lot of time copy-and-pasting text over to websites like pin1yin1 so that it would give me the pinyin equivalent, since I grew up speaking Mandarin, but my reading is rusty at best. I thought it would be useful to have something that auto-displays the pinyin of characters when you select or hover-over characters, and did a quick search to find ChinesePera-kun. After following the instructions to install it for Firefox 3.5, I enabled it by clicking on the little blue circle on my toolbar to toggle it on. This is what it looks like if I hover over something:
Very slick! This is a huge timesaver for anyone learning Chinese.