'Mash-up' has become more commonly associated with the merging of software, in particular websites or applications built using content from more than one source to create a new service. Typical examples include Nightfeed which combines social networking sites such as Facebook with Google maps to help you find the most popular nightlife in your area; Twittervision ,which displays Twitter posts on a global map in real time; and SoupSoup, a news mash-up that complements stories from the BBC, CNN and other sources with articles from Wikipedia and pictures from Flickr. Since you don't need a degree in computer science to build a mash-up and the tools to do so are readily available, there are already thousands of such applications on the Web, covering everything from shopping to real estate.