MarketScore is a spyware program, which are computer applications that collect information about users browsing activity, preferences and interests. The data collected is sent to the creator of the application or third-parties, either directly or after being stored on the computer.
Spyware can be installed with the user consent and awareness, but sometimes it is not. The same happens with the knowledge or lack of knowledge regarding data collected and the way it is used.
Additionally, MarketScore registers itself as LSP (Layered Service Provider), in order to harvest users' information about their connection, such as Internet usage, pages viewed, phone connection details, inventory of the applications installed in the computer, etc.
LSP (Layered Service Provider) is a Windows feature that allows to specify a number of programs, in order to process all the TCP/IP traffic taking place between Internet and the applications that are accessing Internet (such as the web browser, the email client, etc.).
For example, it could be specified a computer security program, which analyses the traffic in search for viruses or other threats before transferring it to the final application of the traffic.
However, this structure can also be used by adware and spyware programs, in order to intercept the communication across the Internet, and, what is worse, if they are deleted without taking precautions, the Internet connection will stop working indefinitely.