Hi just installed whatapp on my android. I only want to use this when my Wifi is in use. I found out that there is no way to sign out of this messenger. I don't want it running in the background using my data. Some1 told me to clear my data after every use. Meaning that I have to add my # & contacts all over again. Are my previous messages that were sent suppose 2 be there? Plus if I clear all my data 4 whatsapp does this mean whatapp is not running in my background? Trying to get a confirmation on this as I'm worried abt using my data as I know this takes up alot.