1.The use of web technologies in k-12 is a topic I feel half and half about. It depends on the grade level you are teaching for the amount of exposure. I think younger kids should just get a glimpse of the internet and not go too much into depth. This is when they need to learn about more important topics rather than how to use a computer. I want to teach first grade and I don't think I will even teach them anything about the internet that is way to young to start using a computer. I think about 6th or 7th grade students should start to learn what the world wide web is and really start to get their feet wet so they can be prepared in high school and college.
2. I think wikipedia is a good way to get knowledge about things that interest you or to get a simple understanding about a topic but not for school papers and things of that nature. There are books and other internet resources that would help students learn about something rather than wikipedia. Although wikipedia does not get credit for the fact that after a certain amount of days if anyone posted false information on a topic it is replaced with the correct information. But again I would not suggest to use it for papers or powerpoints.
3. I know wiki will not help me with anything I have to do in my profession yet alone do anything for me in my own personal life. I just find it to be one of those pointless internet communication resources. I feel like mostly all of them do the same - blog pages, twitter, and wiki and many more are completely pointless. I want to teach first grade and this would be too advanced for them - anything on the computer would be too advanced. But even if the winding road takes me to teach high school I would never bring the things I learned about wiki or wiki into my classroom.