If you are into genealogy like me, a site like Obituaries Australia could be a great help. It is even a great site for those who may from time to time need to find out information about a deceased relative or friend. Obituaries Australia is an online database of obituaries published in various print media and is searchable in a variety of ways.
For more, visit:
http://oa.anu.edu.au/
AnswerGarden is a very useful web application that can be embedded into a website. I use the embedded widget for feedback on one of my websites, but it can be used for a variety of purposes such as a guestbook or poll. It is available for free.
Thumbscribes is a place for creating collaborative content and materials. You can co-write a story, a poem, a song, etc. You can also use a variety of devices when using ThumbScribes.
Have a look at:
Kevin's Daily Photo, Video, Quote or Link 