Are my supernodes used for any other site / are my users' browsers used for any other site than mine?
With regards the first point we should detect it (based on you ASN, if you are on 3g modems they won't be able to upload). E.g. even though your laptop/tablet is on 'Wifi' your actual IP that comes to the backplane will be from your network block (the cellular address block) and so your client will be automatically removed from the available upload pool (although you can still download). Feel free to PM me directly if you've more questions