Bathyscaphe

2ch (pronounced Ni Channeru) is Japans largest and most successful bulletin board which covers topics from unemployment to gardening to Akibakei - Japanese geek stuff - Otaku and what have you.
Normally, one would go to 2ch.net and choose what category to view from there. People can then leave messages using the web interface and read the latest dodgy underground stuff too...
If you saw the Japanese drama series Densha Otoko, you would have noticed that they were all using a chat board - its 2ch but they called it "A ch".
If you really want to know whats going on above and underground in Japan - you need to delve into the world of 2ch - its the only place where you can read about whats *really* going on.
Despite the really odd name of BathyScaphe, this app has to be the best 2ch reader I have tried to date. Threads refresh when there is a new post and you can search multiple threads at the same time. You can also keep bookmarks of your fav threads and you dont have to endure the ads that you get on 2ch. Well put together and recommended.