日本語 Japanese Ask Questions Thread 4

If you have a question about the language, ask it and fellow 4channers might see it and answer it for you.


Japanese Ask Questions Thread2
http://dis.4chan.org/read/lang/1206158123/1-40

Japanese Ask Questions Thread3
http://dis.4chan.org/read/lang/1267485093/1-40

So could somebody tell me how Kanji, Hiranaga, Katakana, etc all tie in together and what approach to take in learning it.

Are all of these used in modern Japanese? or are some of the written languages like Cursive where it is just for style? (and for the most part obsolete and could be ignored)