If you like customizing your device in ways that Apple would never allow you to, then you might be interested in checking out a new free jailbreak tweak called anyBadge
by iOS developer Javier Brito.
With anyBadge, you can literally set the notification badges of any application icon to just about anything you want. After you install the tweak, and you attempt to open an application (like the Settings application, for instance), you will get a pop-up like the one shown above asking you to input badge text. When you input the text you want, and then tap on the "Enter" button, you can exit to your home screen and take notice at the fact that the application you were just in now has an application badge with the text you put into the text field.
The pop-up appears every time you open an application, and if you choose that you don't want to set any badge text for the application you open, you can just tap on the "Cancel" button to exit the text field box.
AnyBadge supports text characters, numeric characters, and Emoji. You can enter up to about 5 each of text or numeric characters, or up to 2 each of Emoji. You can also have custom badges on as many application icons as you want.
After a while, the pop-up always showing up can get annoying, but luckily, the tweak adds a preferences pane to the Settings application where you can easily enable or disable the tweak on demand. Disabling the tweak will not delete your custom badges; it will only disable the text field pop-up from appearing when you open applications:
If at any time you want to remove your custom badges from application icons, you'll need to make sure the tweak is enabled, open the applications you want to remove the badges from, and in the text field pop-up, just leave the text field blank.
For what seems like a really simple way to customize your device, anyBadge is a really cool and entertaining way to make your device stand out from everyone else's. The tweak only works with iOS 7 devices. If you want to give anyBadge a try, it's available for free in Cydia's BigBoss repository.