As more of us around the world join the web, a lot content is going to start to be produced in non-English languages. This hasn't been a factor for a lot of us, but I suspect it will as we begin to discover content-rich resources and individuals we want to interact with.
Case in point. Recently I started reading a German blog that covers technology. It has a lot rich content, like for example the latest build of a portable version of Google Chrome - but it's all in German.
I was delighted to discover that not only can Google Reader translate RSS but it remembers this setting on a feed-by-feed basis. Even though the translation is Yoda-like it's incredibly handy and is opening up my eyes to new voices. I hope that the big social networks like Twitter and Facebook can one day follow suit.
I use tweetdeck to translate w/ french and spanish friends. not sure if I have tried japanese or chinese. a very useful tool.