I have a bit of a love-hate relationship with e-portfolios, personally. I think that they could be incredibly useful, but my own experience with them has been lacking. When I was in my teacher training program, we had to complete an e-portfolio, which was not much different than a standard paper portfolio, except that I did not have to carry around a large binder with all of my work. As such, I do not feel like the technology was being utilized to its greatest potential. I think that electronic portfolios can be so much more valuable, because they can enable the creation of artifacts with greater diversity--with the inclusion of video and other media. In my experiance, eportfolios have frequently been used as showcase portfolios, or a product showing achievement. But could this use also be an example of that final summative assessment--that test on a Tuesday that shows everything you are supposed to have learned? Granted, the application of a portfolio over a simple test does lend itself to a longer, more proceedural view of the learning, but it does not, by itself, shift the assessment into a more formative stance. 

E-Portfolios, however, have great potential to aid the learning process when flipped from a showcase product to a working process. This shift is much more difficult if the portfolio were simply done on paper. The ability to create and utilized blogs, wikis and other electronic means of information gathering and reflection can bring great power to the electronic portfolio. And being able to have others review and critique these electronic artifacts--at any time and any place, makes the tool even more useful. e-Portfolios are but one way we educators can help with the development of ubiquitious learning. The learner creates artifacts in the digital environment when and where they can; the reviewer can critique at their convenience, and the teacher can analyze for understanding in a formative way and a summative way based on the stage of the portfolio's development.

Breakdown of e-Portfolio uses development

https://sites.google.com/site/eportfolioapps/overview