If you have a question about the language, ask it and fellow 4channers might see it and answer it for you.
日本の方からのご協力も大歓迎です。


■USEFUL TOOLS

Rikaichan
http://www.polarcloud.com/rikaichan/
A pop-up dictionary for Firefox that shows readings and definitions when you hover over words.

Rikaikun
https://chrome.google.com/webstore/detail/jipdnfibhldikgcjhfnomkfpcebammhp
Same as above, but for Chrome.

Anki
http://ankisrs.net/
Flash card program mainly useful for vocab and kanji repetition. Can sync decks between computers and your phone.


■WEB-BASED DICTIONARIES

ALC
http://www.alc.co.jp/
Offers a web interface to the Eijirou dictionary, made for use in translation work.

kotobank
http://kotobank.jp/
Pretty good for J-J lookups. J-E/E-J definitions from Progressive.

Tangorin
http://tangorin.com/
The best interface to Jimu Buuriinu-sama's EDICT, which is a mess, so don't use this unless you have to.

weblio 類語辞典
http://thesaurus.weblio.jp/
It's an extensive thesaurus.

(If you want the best J-E/E-J dictionary, get an EPWING copy of Kenkyusha.)


■MEDIA

D-Addicts
http://d-addicts.com/forum/torrents.php
It's a horrible community, but it's THE go-to for drama series. Many variety shows turn up there as well.

JPopsuki
http://jpopsuki.eu/
It's a private music tracker with an extensive selection of just about everything.

KeyHoleTV
http://www.v2p.jp/video/english/
An application that lets you stream live TV in shit quality.

Tokyo Toshokan
https://www.tokyotosho.info/
anime anime anime anime anime


■PREVIOUS THREADS

See >>2 for links.