Well here's a surprise!
Sam Dealey in The Hill - Donations to Sen. Edwards questioned:

Sen. John Edwards’ presidential campaign finance documents show a pattern of giving by low-level employees at law firms, a number of whom appear to have limited financial resources and no prior record of political donations.

Records submitted to the Federal Election Commission (FEC) show these individuals have often given $2,000 to the North Carolina Democrat, the maximum permitted by law.

In many instances, all the checks from a given firm arrived on the same day - from partners, attorneys, and other support staff.

Some of these support staff have not voted in the past, and those who have voted include registered Republicans, according to public records on file with various county registrars of voting.

Edwards’ campaign records also reveal that many of these individuals’ spouses and relatives contributed the maximum on the same day. The Hill found many of them to be first-time givers. Some have no previous demonstrable interest in politics, while others appear to be active Republicans.
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A 2002 survey conducted by the Legal Assistant Management Association (LAMA) found that paralegals earn an average pre-tax salary of $44,416. Clerks make $30,345 on average, and managers receive $81,151. LAMA noted that salaries for legal assistants in San Francisco, San Jose and Los Angeles tend to be 11-29 percent higher than those nationwide.

Jennifer Palmieri, a spokeswoman for Edwards, told The Hill that the pattern of low-level employee contributions "doesn’t concern us" and that the Edwards campaign is "proud of our compliance record."

Many case studies of individual contributors by following the link.