Assuming that behavioral targeting does not work, which I do not know, several possible reasons:
1. They started tracking when behavioral targeting seemed like a reasonable hypothesis, and keep doing it now to build a dataset in case it might work in the future.
2. Google does lots of things that are speculative and generate no revenue, and the general attitude in the industry is "why not collect all data we can because storage is cheap in case we can somehow use or sell it later". If we applied your overall logic to every part of Google, they would probably have 500 employees.
3. If Google can persuade advertisers that it works, they still make more money from them even if Google knows that it does not. Thus BT can generate value for Google without generating any for advertisers.
4. If everyone else in the industry also makes these claims about behavioral targeting working, any company not claiming to do it too would be at a competitive disadvantage.
Also, it is possible that BT "works", say, 1% better than CA. In that case it technically "works and generates value" but most reasonable people would say in that case that it does not justify the privacy tradeoffs or general hype.
1. They started tracking when behavioral targeting seemed like a reasonable hypothesis, and keep doing it now to build a dataset in case it might work in the future.
2. Google does lots of things that are speculative and generate no revenue, and the general attitude in the industry is "why not collect all data we can because storage is cheap in case we can somehow use or sell it later". If we applied your overall logic to every part of Google, they would probably have 500 employees.
3. If Google can persuade advertisers that it works, they still make more money from them even if Google knows that it does not. Thus BT can generate value for Google without generating any for advertisers.
4. If everyone else in the industry also makes these claims about behavioral targeting working, any company not claiming to do it too would be at a competitive disadvantage.
Also, it is possible that BT "works", say, 1% better than CA. In that case it technically "works and generates value" but most reasonable people would say in that case that it does not justify the privacy tradeoffs or general hype.