QIHU 360 SOFTWARE security products (a.k.a. 360 Total Security) are all offered for "free". That means, people may use them without purchasing them.
However, businesses, like QIHU 360 SOFTWARE, unfortunately cannot run on thin air. They need a source of income. QIHU uses these notorious controversial data mining techniques to gain revenue from advertising companies to whom they "lease" it.
I'm very certain, however, that, to at least some extent, this data is anonymized, so that no "real" sensitive information is released to the 3rd parties; only "statistical" data is released.
Take another company for example: Comodo Group, Inc.
That is the company that develops all COMODO products, which are quite popular, and of course, they develop offer their very well trusted
SSL Digital Certificates.
Products like COMODO Internet Security Premium, COMODO Firewall, COMODO Antivirus, Chromodo, Comodo Dragon, COMODO Cleaning Essentials, are all offered for free to home and small business users, with a free "lifetime" license.
However, again, this software isn't developed on thin air.
The costs for its development is covered primarily by those
SSL Digital Certificates which COMODO offers.
In other words, a company
must be paid in someway in order to continue maintaining their products.
This is the basic idea. All in all, I believe there is no serious privacy issue to be afraid of from 360 Total Security.
Make sure, however, that you always download it and install it from the main website:
360 Total Security | Download Free Antivirus for PC,
as other websites may bundle the product with other junkware, such as toolbars and other tracking software.