1. Wiki Definition, https://www.answers.com/topic/wiki
2. Blog. https://www.educause.edu/ir/library/pdf/ELI7006.pdf
3. Picasa. https://picasa.google.com/
4. Podcasting. https://en.wikipedia.org/wiki/Podcast
5. Adamic LA, Buyukkokten O, Adar E (2003) A social network caught in the web. First Monday 8(6–2):1–21