Category tags
I use category tags to sort things by grade. The categories can then function as a search term to bring up all of the things for one grade level: first grade for example
Now, for the wiki magicians: if you can come up with a way to combine categories (for example 'biology' and 'first grade'), then category pages could function as Boolean searches for subject AND grade level AND resource type (lesson plan, image, etc).
A consistent list of category tags would be needed for this all to work. In the absence of the Boolean idea, a table of categories could be established:
| Subject | Grade 1 | Grade 2 | Grade 3 |
| Biology | Biol1 | Biol 2 | Biol3 |
| Poetry | Poet1 | Poet2 | Poet3 |
Generators of content could liberally sprinkle in the categories that best described their content.Dmccabe 04:08, 19 November 2007 (CET)
see: http://meta.wikimedia.org/wiki/Help:Category#Subcategories might be what you're after.
