However we can still find the difference made by technology. When thinking about communicating with someone, we would tend to dial his or her number by picking up a phone rather than conducting a face-to-face talk. When we want to inform others a certain thing, we are more willing to leave instant messages rather than writing a letter or note. People are using technologies everyday and they indeed affect our society in various aspects including customs and ethics, but is it a crucial factor that could "determine" the social customs and ethics? I greatly doubt that.
Technologies are only assembles of people's thinking, so they are totally decided by human begins themselves. So the people who are living in certain customs or ethics won't develop the technologies that disagree with their customs and ethics. Take the first clone sheep Dolly into consideration, when people first heard of that from the news, they felt into deep panic and the ethics makes them to image what will be if the similar technology be conducted on human beings. The ethics system will instantly collapse if one day we find another "ourselves" exist with same faces, finger prints and characters. Fortunately, most country banned this kind of research under the pressure of their people--the ethics in their mind would firmly prevent such things from happening. This is ethic, which determines the fate of technologies but not the opposite.
So does the customs. When steam locomotive was initially invented, its roaring noise and enormous figure drove people away. They treat it like encountering a fierce animal and even thrown stones at it trying to stop it. The misunderstanding of train was not clarified for a very long time. From here, we can clearly see that technologies are always not first accepted by the society under its old and traditional customs and ethics, and therefore there is no possible for technologies to "determine" the social customs and ethics.
But technologies can greatly influence people's way of life and thus influence their way of thinking, which finally cast impact on social customs and ethics. But technologies can not determine them, especially when it goes absolutely against social customs and ethics. Email is a good example: it creates the possibility for people to transfer messages without providing any additional information---no address to show where the writer is; no handwriting to show the emotion of the writer when presenting the views and no envelop and notepaper to provide a glance at the characters.
Under such influence, our customs and ethics can be slowly changed. Look back to the example of invention of train, when people found it useful and not harmful to their customs and ethics, they will gradually accept it and let it influence their daily life just like phone and email does referred in the first paragraph.
In sum, I'm not denying the technologies could influence our daily life as well as social customs and ethics. However, technologies are by no means the crucial factor that could determine social customs and ethics, while social customs and ethics would hold the fate of technologies.