If art is supposed to provoke the viewer, Eva and Franco Mattes are doing their job well. The Italian artists are the masterminds behind 0100101110101101.org, one of the earliest instances of 'net art on the Web. For many years the couple kept their identities secret as they performed actions such as hacking the Vatican website and manufacturing the persona of Darko Maver, who was invited to exhibit at the Venice Biennale before he was revealed as a fake. In recent years, Eva and Franco have been working more publicly as they take on virtual realities and online pastimes such as Second Life and Chatroulette in their work. So it is with their new show, “Colorless, Odorless, and Tasteless,” which opens Friday in San Francisco.