My iPod touch was stolen. If the person type the wrong password 10 times, it will erase all my data. And, if that happens, will I receive the notification ("find my iPod") I requested in iCloud when it goes online?
No (for iOS 6 and earlier) - erasing an iOS device means you will never hear from it again. No messages, no tracking, no find my device since at that point. Even if "your device" checks back in with Apple, it is no longer associated with your account.
This is covered by Apple here in this article:
After you erase all the information on an iOS device, you won’t be able to use Find My iPhone to locate it or send it a message.
Someone can enter a new (or your account) back into that device and only then will it resume checking in with the new account/password combination to be tracked.
The only way you might get a notification is if you first send the locate message and then the erase message and both remain queued in the proper order. Since the device was offline when you sent the two commands (otherwise you would have located the device if it were online), the device could later check in and it is conceivable you will get the locate notification delivered with enough time to respond before the erase command gets sent and acted upon.
Apple changed this in iOS 7 where activation lock and an enhanced lost mode can erase the device except for the tracking and registration. This brings the erase benefits without losing control of the device.
Devices do not push notifications back to iCloud in the manner you suggest. It's actually the reverse, you can push a notification (including sound) and receive location information from the device, but when you restart, begin reformatting, or get the 10 failure lockout on a device, the device does not "phone home" before beginning it's lockdown procedures. It just locks down right off the bat.
The ability for you to interact with your device after being stolen is limited to the options available via the "Find My iPhone" iOS app on another device, or via iCloud.com.