Teaching with Moodle

Hi all,
we have just started using blogs with our students, they love writing them which is supported by our literacy and writing policy.

However, so that I can track the blogs by my students from 1 course from another I use site wide blog tags. I need to search through the blogs by using tags, can I search using tags and by using more than 1 tag to isolate / find those tahat relate to one class project frtom another, or do my tags need to be very specific eg 20079ISACompStudVirtualPcProj, I would prefer the students to use a number of tags eg 2007, 9ISA, Compstud, Project, etc

I really like the idea of blogs and the students like them too and are writing blogs for other areas as well.