Scott Leslies post on PLEs is a good collation of the elements he has observed when looking at  other PLEs.  Scott’s PLE Wiki is a handy reference point for some of the best representations and thinking in this area. The mistake made with PLEs is to associate it as a single space -ePOrtfolio or Desktop- but more about interrelationships and the way we use  such tools to compose and relate /define our knowledge network. As Scott says -A PLE -is a conceptualization, is an incredibly valuable one…  Knowing how you learn, and how you conceive of the structures and relationships that support your learning, is an important step to becoming a master learner. Scotts diagram works as a distillation of this.