For those Japanese learners who understand a good amount of Kanji, grammar constructs, and vocabulary, your options for study materials are drastically increased. Thats because you can use sites and books that native speakers would use. I’ll introduce a few of my favorite resources in this post.
This site is extremely valuable for learning Japanese vocab and grammar you don’t see elsewhere. It’s a question and answer site, something like Yahoo Answers, except that most people on this board are extremely polite. As you probably already know, ‘polite’ in Japanese doesn’t just means avoiding rude statements, but it means a whole different set of polite verbs and other words are used, things like “お答えいたします”. Not only is this polite style pleasing to read, but it’s good to learn for your own use.
The second thing is that the subjects on here mostly relate to real life problems, for example something like “How do I propose to my girlfriend?” or “What should I do about XXX medical condition?”. You could read fantasy novels and manga for years and never encounter much of the vocabulary used. If you aren’t living in Japan and plan to some day (or are and having a hard time), then this site is a must read. I’m not referring to the answers themselves, but the grammar and vocab that is used to express them.
And finally, this site is free and questions can be submitted by anyone with an account. Feel free to submit your own questions, just read through some existing questions first to get a feel for some of the common polite expressions used by others, and try to imitate them. You might have a hard time finding a good English message board where native Japanese speakers will answer your questions about the Japanese language or culture, but you should have an easy time finding a native speaker to answer your queries on this site (in Japanese).
２）知恵袋 Yahoo (http://chiebukuro.yahoo.co.jp/)
This site, whose name literally means something like “Bag of wisdom”, is very similar to the 教えて goo in that you can ask questions about practically anything and have them answered.
３）Goo 辞書 (http://dictionary.goo.ne.jp/)
This is a massive multi-site which contains many useful, free dictionaries. I discovered it a few years into my Japanese studies and haven’t stopped using it since as my first line of defense when I need to know a meaning of a word, or when doing translation.
This site includes 国語辞書、英和辞書、和英辞書、類語辞書、専門用語集、and a Wiki as well. This pretty covers anything you could ever ask for dictionary-wise.
For example, the 和英 dictionary covers looking up English meanings of Japanese words, and includes each meaning variant with multiple detailed example sentences with English translations of those.
If you really want to get the full details on a Japanese word, switch to the 国語 dictionary which gives meanings in Japanese, coupled with ample example sentence (例文) pulled from classic works in 青空文庫, and common expressions utilizing that word (慣用句).
４）Amazon Japan (http://www.amazon.co.jp)
This site is great for seeing what products are popular in Japan and for even buying those, assuming you can afford the time and money to ship them across the ocean (if you are not living there).
However, there is a great hidden source of reference for Japanese learners looking to increase their ability to express themselves – product reviews. The ability to describe your feelings about a product (including books, manga, movies, etc.) isn’t something which is explicitly taught in many text books. As a result, if we tried to write our review of something we might stop at「面白かったです」.
I’ve tried to make a habit of writing reviews of Japanese books I’ve read (in Japanese), and these reviews provide a goldmine of expressions to use in this type of 感想文 writing.
Another neat thing about these (and other) Japanese sites is the advertisements that come up. They target native Japanese, and of course are in Japanese, so they provide an interesting window to modern Japanese culture.
Have you ever used alc.co.jp ‘s dictionary （英辞郎 on the WEB）? It is fantastic! It is full of snippets from previously translated news articles, websites, and such. Therefore, more than just a dictionary, it is a phrasing resource. Whenever I want to know a phrase or slang term, I turn there.
I think I may have run across it once or twice on the web but now that you mention it, it does seem to have great examples. I’ll have to try using it more next time I need help with a word. Thanks!