hmmmmm....
well, the original intention, i think, was for each level to be completely isolated, but what we've found is that while some people do stick to one level (as intended), most people tend to hop around... or some listen to everything. others listen to the current lessons as they come out, but then go back and review seriously old lesson at their particular level. so the way people use the site is really all over the place. i don't want to say it's up to you, cuz you said you don't want to hear that, but...
i guess what i could say for the theory behind beginner and season 2 and season 3 is this:
the original Beginner series was intended to progress in a linear fashion. each lesson built on the previous lesson. somehow after 100 beginner lessons things got pretty wild... i mean advanced - really advanced.
Season 2 and Seaon 3 were designed as non-linear courses. this is for people who have the basics down but want reinforcement and practice. i've noticed a lot of quite advanced students listen to these stories still simply for the practice.
the Nihongo Dojo Newbie Series was meant for the absolute beginner with no prior knowledge of Japanese except maybe "sushi" "sayonara" and "karate." like the first beginner course, this has been designed in a linear fashion. again, each lesson builds on the previous lesson.
if you can listen to this week's newbie lesson and find it too easy, try this week's beginner. if that's too easy, try this week's lower intermediate. and so on....
if you are somewhere in between levels, that's ok! you can always search for topics, function, grammar points, etc with the lesson tags on the site. the grammar bank in the learning center also references lessons, i believe.
the current Newbie Series (Nihongo Dojo) will eventually end. and when it does, Season 3 will end and a new linear Beginner Series will start.
the site will stay dynamic and always be evolving. this way we can always try new approaches and new methodologies.
oh, one more thing about the Learning Center
if you use it the way it was intended, after you do the content questions, grammar questions, read the pdf's and practice pronunciation and listening with the line-by-line audio, you can check the lesson as completed. this is a way to systematically go through all of the lessons of a particular level.
i hope this was helpful...
i think the most proactive listeners on the site take radically different approaches. for example, watermen is very systematic and thorough and seems to be going through all of the levels at the same time. other listeners are jumping around based on grammar points or interesting topics.
i'd like to hear what other people are doing
marky