Why do ads use so much data?
Because an ad is rarely just a picture. Filling one ad space usually means downloading an ad network’s script, which runs an auction, contacts other companies, fetches the winning ad and loads tracking code for several of them. Video ads that play on their own are the heaviest of all. A page with several ad spaces can download more for the ads than for the article you came to read.
How does blocking ads save data?
A blocked request is never made, so it costs nothing. AdFender checks what a page asks to load before it is downloaded, and refuses the ads and trackers on its lists. The script that would have pulled in a dozen more files never arrives, so neither do they. Blocking after download would save nothing; blocking before it is the whole point.
Hiding is different. Some rules hide a part of the page, such as an empty ad frame or a banner, rather than blocking a request; what they hide may already have downloaded, so it saves space on your screen rather than data.
Where does AdFender show the data it saved?
On the dashboard. Est. data saved shows how much AdFender has saved you since it started, beside the counts of ads and trackers blocked, and the All time panel keeps the running total since you installed it. The figure is an estimate: something that was never downloaded cannot be weighed, so AdFender estimates each blocked item from typical sizes.
When does saving data matter most?
- Metered connections: a phone hotspot, a mobile broadband plan or a data-capped home connection, where every megabyte counts.
- Slow connections, where less to download means pages that finish sooner.
- Laptops on the move, tethered to a phone or on hotel and travel Wi-Fi.
What does it not save?
The content you actually want. A film you stream or a file you download is the same size with or without an ad blocker, and sites with few ads change little. The saving is on ad-supported sites: news, recipes, forums, free video and the like.
Less to download also means pages settle sooner: do ad blockers make web pages load faster?