Generally yes , but the answer also depends on the population being examined, and the answer is the same for both telephone and face-to-face interviews, and not only for the Internet. If a representative sample of these people can be reached by any of these methods of interviewing, the answer is yes , the research can be trusted.
What guarantees the representativeness of each sample is randomness, or rather the possibility that each individual can be selected into the sample. In this way, when we look at the entire population, the most important thing for our sample is that each individual has the possibility to be selected in the sample. Face to Face and telephone surveys allow us to meet this condition, precisely because a large number of the population lives at a certain address and owns a telephone. But with modernization and a large number of individuals using computers and the Internet (in 2015, data for Serbia show that as many as 64.4% of people used a computer and 63.8% used the Internet), the opportunity for well-organized online research to be representative opens up. In addition, there are places and populations where it is very difficult for an interviewer to obtain a representative sample using Face-To-Face interviewing, and there are also places and populations where only certain classes of people have access to the telephone or the Internet.