The wide penetration of Internet brought to life new realities unknown so far to society. One of these realities proves to be the use of Internet for sending billions of unsolicited communications known as spam, at practically no cost. On the one hand, commercial communications serve as a base for the turnover and the development of e-commerce. On the other hand, however, these communications eat huge amounts of peoples daytime resulting in shortening the usable time for generating effective gross domestic product. On a large scale, the damage to society is huge. Moreover, instead of increasing the turnover, the spam leads to damages to addressees due to the generated substantial traffic. To fight this new realm, lots of technological solutions came into life. Inter alia, these involve the usage of spam filters and blacklists. As the essay will show, the usage of these useful from practical point of view technologies proves to be on the edge of legality. They might reveal the secrecy of the communications and might seriously harm the bona fide users in their relations while using the Internet. The article will raise questions on the legality of these realms.