In reply to Luciana Annunziata.

One approach is to create a unified performer facing environment:
http://jarche.com/2010/05/a-unified-performer-facing-environment/

I suggested a new model for the training department in the latter part of this post:
http://jarche.com/2009/10/the-future-of-the-training-department-2/

Here's a post on metrics for social networks that may be of interest:
http://jarche.com/2009/05/mapping-metrics/

and some thoughts on ROI: