ePortfolios have two primary components. The "presentational" component is the visible, shiny product of the ePortfolio process. It is a website, or a presentation, or a set of media produced to document and communicate a concept or event.
But, just as importantly, an ePortfolio has a cognitive component. The individual crafting their ePortfolio should be reflecting on their practice of teaching and learning, critiquing what they've done - what worked? what didn't work? what would they do differently? This cognitive or reflective component is crucial, as it allows the individual (and their peers) to learn from both success and failure.