After installing CM10 on my Galaxy SIII, I wanted to check out the newest app out there called CyanDelta. Basically this app is used to download CM10 updates for your phone, but unlike ClockWorkMod, or BBQTools this only downloads what is called a Delta file.
A Delta file is just the changed files in the ROM itself, and it averages about 10 megs, unlike the normal rom which is around 160 megs. This cuts down on the bandwidth used, and the space used on the phone for updates.
From what I understand CyanDelta creates a file based off your last known good ROM, and from there daily it downloads a Delta file. From there it recreates the ROM from the one last night adding the Delta file information. Now that you have a new nightly ROM, you reboot into recovery and start in the install.
Now I have the unlimited plan on my phone so data usage is not such a big deal for me, but for others this is a great app to use. It is very simple to install and was able to get it up and running in seconds with no problems.
The one question I have about the program is that it shows that you can add a second zip file to the program to install on reboot. I tried to add the Google Apps but it would not let me. I may have been doing it wrong as the GAPPS was in my download folder, maybe it needs to be in the CyanDelta folder, will try that next time.