The data that a program receives is called input and data that the program generates is called output. Other times, the data is unknown. If the program were working with a simple algebra equation like, "x + 5 = y," the variables "x" and "y" would be unknown pieces of data. The most popular places to find shareware is within thousands of download libraries, however the companies (and even independent programmers behind shareware) are increasingly offering shareware from their own websites. A simple Google or Yahoo search for a particular type of program will yield all sorts of results that point you toward items that you can try before you buy. There are many creative uses for home networking, however it's an ideal situation when upgrading each computer to the same capability is financially out of the question. On a home network, each computer has access to the equipment of the better machine in the group as if that equipment were their own. Nicotine and tar mean certain death when it comes to computer fans, however should you find a need to clean the fan, do so with extreme care. It's quite easy to cause more damage from cleaning so if you're not comfortable with cleaning your PC yourself, take it to a shop for servicing. Otherwise, you can unplug and disassemble the computer to do it yourself. A team of professional coders build it but the community at large isn't part of its conception. It's costly to produce and as you can probably guess, that cost is passed on to the end user: the consumer. Open source software on the other hand is free. Free to download, free to install, free to use, free to modify, and free to share. The market for these devices extends from the highly technical and professional all the way to the pre-teen socialite. The product crosses all demographics and thanks to decreasing costs - it sees no economic boundaries as well. The Wikipedia encyclopedia claims that "Out of 1 billion camera phones to be shipped in 2008, Smartphones, the higher end of the market with full email support, will represent about 10% of the market or about 100 million units.