Your answer: no (tentative) meaning no UNLESS you screw something up, really bad, so if you can do it without getting any serious errors then you should be fine, but any SERIOUS errors (not like they happen often unless you have no idea what you're doing) and you'll have to do a full restore from iTunes, which WILL erase all of your apps, settings, etc.
SO your answer (in short form) is this:
No, unless you're really really stupid.
It shouldn't but I think that it's better to sync or back up an iPod first just in case something goes wrong
it really just depends on what kind of program you are using, i used greenpoison, and it worked pretty good, redsnow is also okay.
not unless you restart the entire device on itunes no
no it does not but it can cause further problems where you would need to restore all data so I reccommend backing up your data before jailbreaking it.
No
yes
For ps3 you have to go into saved data utility and delete previous memory from there
No, to jailbreak your iPod Touch, simply download the application you wish to use and follow the prompts on screen. Although it is suggested to maintain a backup, it is normally not necessary and the jailbreaking process is normally harmless to your phone. All user data is kept throughout the jailbreaking process.
yes
Just place the card in your PC card reader and select the file to delete. It's the opposite method you use when putting the games on
Touch data can be removed either by updating to the latest firmware or through iTunes,
No. You have to press up-select-b on the title screen to delete your saved data. Then you can start a new game that you can save.
no it does not erase purchase history but wipes out all data on the itouch
by delete data it means delete ALL data. short answer. NO
When restoring your Ipod Touch the data on itunes doesn NOT get deleted. :D
I would say no. Any used game that I have bought from gamestop had previous data from the past owner.
Yes