Jgram is an interesting page for people learning Japanese and are struggling with the Japanese Language Proficiency Test (JLPT – 日本語能力試験). Its goal is to tackle how to learn Japanese grammar, which is one thing that online dictionaries, textbooks, and even many Japanese teachers never go in to to any level of complexity.
Japanese is a language full of colourful grammer, a phrase (or ten!) for every occasion. However, without resources like jgram to bring it all together, learning proper Japanese grammar can be a pain.
I like the focus on the JLPT levels, as it makes it easy to track your progress, and knowing what your level is.