Student Notebooks in the Age of Social Networks

Many teachers have used authors notebooks, science journals, etc. in the past. There is tremendous value in them. But, now that we have easy access to blogs, wikis, social networks, and more, how do we take the student notebook/journal concept and adapt it for today's tools and learning methods? What I'm struggling with particularly write now is which tool is best for my students to conduct ongoing social studies inquiries of various sizes, on a variety of topics, with different partners/groups that I want shared with the class/world. If I go with a wiki, do students record their work on an individual page, a group page, a topic page, or something else? What would be nice would be if the elements on a page could be individually tagged by student, group, topic, method, etc. so that the content could be sorted and sifted in different ways. Students could see the range of their own work if they sort/sift it by their name. Groups could collect their work by sifting for their names and topic. Topical pages could be created by sifting for topics and/or subtopics. An online database would be the answer, but what databases have the ease of use, multimedia capabilities, and web2.0 nature of wikispaces?