Digital Media Tools - web 2.0

Still trying to synchronise all the web 2.0 service I use (blog, twitter, wiki, social bookmarking) into a coherent platform for digital communication - and working out which service is the best for which task, and which is just a lot of redundant nonsense.
We now have the MA DDM course wiki, which is shaping up great. Uptake of the educational twitter service edmodo has been reluctant, so I'm thinking of scrapping it or integrating it somehow into the wiki, to spare people having numerous logins. Currently looking at widgets to enable a real-time elements and easy sharing of links on the wiki space.