https://community.o2.co.uk/t5/Apple/Data-usage/m-p/1019280#M151645 <P>Any app or internet use that doesn't use the GSM network.<BR />So, yes, facebook, whatsapp, safari, Google, email, snapchat, twitter etc.</P><P>Shorter answer is what doesn't use data, which is normal phone calls and text messages only.</P> Tue, 22 Nov 2016 13:10:48 GMT MI5 2016-11-22T13:10:48Z https://community.o2.co.uk/t5/Apple/Data-usage/m-p/1019275#M151644 <P>What actions incur "data usage".? I use facebook, safari, e mail, what's app (very rarely).&nbsp;</P> Tue, 22 Nov 2016 13:04:45 GMT https://community.o2.co.uk/t5/Apple/Data-usage/m-p/1019275#M151644 Anonymous 2016-11-22T13:04:45Z https://community.o2.co.uk/t5/Apple/Data-usage/m-p/1019280#M151645 <P>Any app or internet use that doesn't use the GSM network.<BR />So, yes, facebook, whatsapp, safari, Google, email, snapchat, twitter etc.</P><P>Shorter answer is what doesn't use data, which is normal phone calls and text messages only.</P> Tue, 22 Nov 2016 13:10:48 GMT https://community.o2.co.uk/t5/Apple/Data-usage/m-p/1019280#M151645 MI5 2016-11-22T13:10:48Z https://community.o2.co.uk/t5/Apple/Data-usage/m-p/1019281#M151646 <P>All of the above use data and apps updating or refreshing will use data</P> Tue, 22 Nov 2016 13:10:31 GMT https://community.o2.co.uk/t5/Apple/Data-usage/m-p/1019281#M151646 jonsie 2016-11-22T13:10:31Z https://community.o2.co.uk/t5/Apple/Data-usage/m-p/1019333#M151661 <P>O2 guide on data <A href="http://www.o2.co.uk/help/account-and-billing/understanding-data" target="_blank">http://www.o2.co.uk/help/account-and-billing/understanding-data</A></P> Tue, 22 Nov 2016 16:06:24 GMT https://community.o2.co.uk/t5/Apple/Data-usage/m-p/1019333#M151661 adamtemp64 2016-11-22T16:06:24Z