Don't we all sometimes check an address several times to see if a new transaction has been received or if an old one has been confirmed? I.A.N. will notify you about these events at the moment they are broadcasted to the tangle.
No App has to work in the background of your phone, because the bot watches your address on a remote server. The I.A.N. Java program handles the Telegram communication and evaluates IRI's ZMQ Stream. Therefore, no direct api calls are made from your phone to generate the bot's push notification.
Users enter addresses directly with the bot. A seed must always stay secret and should not be enter. To make sure no user enters a seed, the bot informs the user repeatedly about the differences between seeds and addresses.
In addition the bot does only work if the users agree and confirm that they will not use a seed.
I.A.N. will start watching an address for you if you type: /startWatch followed by your transaction hash. /stopWatch will not only discontinue notifications, but also delete all information connection you with that address.
If decide to not use the bot any longer. You can delete all your data entering: /deleteUser and confirming the resulting dialog.
I.A.N. will give you an overview about the current tangle statistics, if you use the command /showStats. This helps you getting a picture how fast your transaction will be confirmed.
Many different features like promoting a transaction are currently being tested and will be implemented later on.