I can imagine the following conversation with my daugher four years from now:
Hey dad, can you help me with today's homework?... Our teacher told us that now we are in sixth grade each of us have to create a "blog" and write there one essay about what I did last summer.
Seriously now. I remember that when I was in seventh grade or so, all girls in my class were extremely busy writing all sorts of journals containing ad-hoc (child-level) poetry, pictures, images, etc.
And for some reason I think that, in the not so distant future, a large percentage of blogs will belong to... kids. Yes, that's right. Especially those in the 5-8 grade range.
Maybe I am wrong, but I just feel that it makes complete sense. A blog is already the perfect environment for childish thoughts, so they will feel at home. They should able to easily add there pictures on a daily/weekly basis - a cell phone with a camera is a valuable tool to generate incomesurable amounts of content. Also, a scratch pad (Nintendo DS?) whose results can be easily saved in a blog can also be used to serve the same purpose. A blog will become some sort of playground, no, maybe more like a all-purpose dumpster for all drawings, poems, pictures, podcasts, replayable XBox games and whatever else will get them more friends. And of course, an easy-to-use interface to create "secret" posts, that only certain friends can see.
And kids won't be probably very sensitive if someone criticizes their work. I am sure that most of them might simply re-edit posts or even delete the bothering comments without any second thoughts.
Of course, all this will require an extremely well integrated infrastructure to push content from your cell phone, your gameboy (or whatever is the next handheld), your gaming engine to certain sites, etc. Startups, fire your engines...