Because your internet traffic at home moves to and from your devices through your internet service provider — ISP for short — they can see where you go online. An ISP can see what sites you visit, how long you’re on them, your location and information about your devices. An ISP may not know the specifics of what you did on those sites (like what you bought, searched for or read) thanks to encryption, but they could make inferences about you based on the sites that you visited. That personal data can be used by ISPs to create detailed profiles about you. Browsing in private mode doesn’t prevent ISPs from seeing where you go online. But sending your web traffic through a VPN can make it much harder.

Oherwydd bod eich traffig rhyngrwyd adref yn symud yn ôl ac ymlaen o'ch dyfeisiau drwy eich darparwr gwasanaeth rhyngrwyd (internet service provider ) — neu ISP, maen nhw'n gallu gweld ble rydych chi'n mynd ar-lein. Gall ISP weld pa wefannau rydych chi'n ymweld â nhw, pa mor hir rydych chi arnyn nhw, eich lleoliad a gwybodaeth am eich dyfeisiau. Efallai na fydd eich ISP yn gwybod manylion yr hyn a wnaethoch ar y gwefannau hynny (fel yr hyn y gwnaethoch ei brynu, chwilio amdano neu ei ddarllen) diolch i amgryptio, ond gallan nhw ddyfalu ar sail y gwefannau yr aethoch chi iddyn nhw. Mae modd defnyddio’r data personol hwnnw gan eich ISP i greu proffiliau manwl amdanoch chi. Nid yw pori mewn modd preifat yn atal ISPs rhag gweld ble rydych chi'n mynd ar-lein. Ond gall anfon eich traffig gwe trwy VPN ei gwneud hi'n llawer anoddach.