This video is on Wikis. The video gives introduction to wikis in a very simple language. Wikis are collaborative and co-ordinative web tools in comparison of e-mails and blogs because on blogs we can not work together at the same time whereas wikis allow us to work together at the same time and at different places. E-mails are not good at co-ordination.
Wikis are a large language community that involve both the teacher and the learner centeredness. Anyone can edit the information on wikis. Clicking on 'edit' button, information can be edited on wikis. Once we are done with the edition of the information, we can save that information by clicking 'save' button. Link button helps link one page with another. Edit, save and link buttons are  helpful to create a good work on wikis.
Online projects, student involvement and group activities can be done with the help of wikis.