eMarketer found, unsurprisingly, that the Internet is increasingly central to the days of desk-bound office workers, who tend to be a highly educated and wealthy audience. The researcher pegs the at-work Internet audience at 50 million -- about one third of all U.S. workers. Since Internet users at work tend to work in white-collar jobs, they are, on average, highly educated and well off: 70 percent have college degrees and 50 percent have a household income above $75,000.