I have a question that why people scare to show their identity if they are doing legal? Why people do not use real identity??? It makes here a more trustable market!!
protect their privacy from unscrupulous marketers and identity thieves.
protect their communications from irresponsible corporations.
protect their children online.
research sensitive topics.
skirt surveillance
circumvent censorship
see
https://www.torproject.org/about/torusers.html.en