The Programmable Web website has a list of a whole lot of these apps which were created by programmers using JavaScript programming (good grief - I'll never succeed in such a thing!). I did attempt a programming course in object oriented programming using Java and realised it was beyond my capabilities. Hence, I doubt I would ever try creating my own mashup! Going by the number of useless mashups out there, you'd have to really know your thing to create a good mashup.
In the Programmable Web website, it's interesting to see the all time tags used for the mashups.
Here they are:

Mapping is the most common tag used, and so I thought that since I enjoy maps myself, I find a mashup that interests me which includes maps.
I went to the 2nd most popular mapping mashup application called Flash Earth. It's a mashup of different map services - including Google Maps, Yahoo Maps & NASA Satellite images. Looking at our planet and zooming into places facinates me, especially with the use of NASA Satellite images that are updated daily and so clear. I can't however zoom in as much as I'd like to! I think I'll stick to Google Earth for that. But for a mashup of comparing images, it does a good job.
Here are some images I captured of Australia:
Yahoo Maps:

Microsoft Virtual Earth:

NASA:

Others might not find this as amazing as I do! But I wanted to choose a mashup that was popular in the most used category of mashups. This would be more of a recreational thing for me, not to help me in any particular purpose. I'm sure there are mashups out there that can help information managers, particularly those who need to assist clients in finding places, with the use of maps and information about the places i.e mashup of Google Maps and Wikipedia or another site perhaps.
Maybe my group members will discover one they find useful that will shock me! But honestly, just like there's alot of garbage on the net, there's also alot of garbage with the mashups. I wouldn't use most of them for anything!
Next I'll be wrapping up this assignment. It has been great so far. A learning experience, despite my knowing a few of these Web 2.0 tools, however working in a group and in class has given me insights into the uses of these tasks as a whole. I will share them in my next blog! Hope my group members will catch up ---!!