Running an email marketing campaign? Which day you should email may differ based on if your target demographic is B2B or B2C:

Business-to-business (B2B) e-mail is best sent earlier in the week. B2B e-mail received on Monday or Tuesday gives readers the opportunity to address the message before the week's the business takes over. Thirty-three percent of survey respondents said they prefer to receive e-mail on Monday, and 36 percent on Tuesday. Preference for the remainder of the week declines sharply each day.

The best day to send business-to-consumer (B2C) e-mail isn't as easily determined. Preferences peak for receipt on Wednesdays (26 percent) and Fridays (31 percent).

Read this Clarity on Best Day to E-Mail article for more information and an invaluable graph.