Most Linux distributions pack a decent load of programs and tools, so when you install one, you do not really have to spend too much time tweaking and polishing and adding new stuff. The multi-hour ordeal of fixing the base operating system, the kind of thing that is rather popular with Windows users, is not a must with most Linux distributions. However, sometimes, no matter how well packaged the base image is, some customization might be necessary now and then.
If you happen to live in a part of the world where Internet is paid by the byte, or gigabyte, you might be very conscious about how freely you utilize your connection after installing a new Linux distribution. For you, the trivial but costly task of downloading several hundred MB worth of new applications might be too much, especially if you like to test software a lot. So let's try to make it less expensive, shall we?
This rather self-explanatorily-named program is a utility available for Linux distributions that use the Debian package manager (DEB) and the APT package management system. It is designed to gather all downloaded packages already available in your package manager cache, and bundle them into a single ISO file, which can be distributed offline.
Every time you launch the program, it will scan the cache and present you with the available packages. You can then mark the desired content, usually all of the stuff found there, and when you're ready, burn the archive. This does not mean creating a CD/DVD just yet, but an ISO file.
You can then share this ISO with your friends. A common round-robin scheme could be where one person downloads all of the content one month, then gives it to their friends, and then, another month, someone else follows the same routine, reducing the overall network utilization and cost. For those with a slow connection, this can also significantly speed up the deployment time. After you install a Debian-based distribution, it can take a long time to grab all the codecs and extra software you like. This way, you gain a local install speed.
APTonCD has its limitations. If you like to clean your system cache now and then, often using the triplet of popular commands like sudo apt-get clean, followed by autoclean and then autoremove, your cache will be empty. You will not be able to utilize APTonCD in this manner. This is worth remembering, as a general rule, especially if you sometimes tend to remove packages and then reinstall them.
If you're blessed with a fast connection, you should also be familiar with the -d flag for apt-get. It stands for download only, and it lets you retrieve the packages without installing them. They will be available in the cache, but won't be installed to your system. This way, you can grab several GB worth of programs, create an archive with APTonCD, burn them to DVD and hand them out, without really cluttering your own box.
APTonCD is a fairly useful tool, especially for people with expensive, capped Internet connectivity or a slow line, who cannot afford to spend hours downloading packages to their Linux box. If they happen to run a Debian-based system, this utility can save them time and money. And maybe help them gain new friends, too.
I did discuss the option of remastering large images, containing lots of useful extras and sending to people abroad in less privileged locations, in my somewhat older broadband Internet discussion. Look it up, if you will. Since, the situation has changed somewhat, but there are still hundreds of millions of people who would greatly benefit from having all of the packages they need locally, at the tip of their fingers, on physical media. If you're willing to help, now you have the technical means to do so.