If you keep being asked to 'report your position' or 'report your next turning point' it's possibly so the controller can monitor your progress and ensure you are still ok and are not geographically displaced, or worse. If you under a FIS, chances are you will have been allocated a squawk that denotes an a/c under a FIS. With potentially 10s of FIS on frequency in a limited geographical area it's just another way of extending a warm fuzzy feeling to the GA community who know they're being listened to/monitored. You probably don't need to keep reiterating the QNH you're on but an altitude update is always handy. If you've manouvered due to Wx or some such reason then we can keep you informed of any relevant info. Just keep it succinct and leave out the 'this is G ****, currently ***, er turning left, er to avoid a cloud, er, ummm etc.
