Help Data Manager

[11mess]

OK So I was messing around with the settings and I came across the Data Manager in the Settings menu. I clicked the Background Data Tab and it says:

"Disabling background data extends battery life and lowers data use. Some apps may still use the background data connection."

Questions...Does this mean if I want emails, facebook or twitter alerts I have to push it to receive or will they automatically pop up like they have been? I know I could just wait and see but honestly what fun is that? I figure someone on here must know what is better or the optimal setting.

Thanks again...