At the simplest level, Mahara is two things: an ePortfolio and a social networking system combined.
An ePortfolio is a system in which students can record ''evidence of lifelong learning'' -- such as essays, files, artwork or other such things they produce that can be stored digitally. This information is collected on Pages which you can create and share. Using groups creates an area to share pages and collaborate with members of the group.
But Mahara is much more than just a place to store files. Mahara also includes blogging, a résumé builder, and Moodle integration. With Mahara, you control which pages and what information within your portfolio other users see. You can have as many pages as you like, each with different content, images, intended purpose and audience. Your audience, or the people you wish to give access to your page, can be added as individuals or as a member of a group. It can even be made publicly available.
For example you could create:
A page for your tutor, which includes assessments and your reflective journal
A page to showcase your best work and résumé for potential employers