American professors Christopher Danforth and Peter Dodds of the University of Vermont have played Big Brother to find out which days we love and which days we dread.

The professors scored words out of nine according to how positive or negative the terms were. Words such as "fun" and "free" scored above eight, compared with words like "hatred", "cruel" and "betray", which scored less than two.

The researchers studied more than 2.4 million blogs, including Twitter, to see what people were writing and commenting on. "They [online users] think they are communicating with friends, but since [most] blogs are public we're just looking over their shoulders," Professor Danforth told Telegraph.co.uk.

As expected, Saturday and Sunday ranked highly, but surprisingly Monday was perceived as the second happiest day of the week. As the week wears on, the positive feelings subsided, with Wednesday — or "hump" day due to its proximity to the positive downward slide to the weekend after the week's peak — judged to be the lowest day of the week.

"People's daily experience is being reflected somewhat in what they're saying. And this is more of a story, we think, for Twitter messages, which we've just started to pay attention to, about a year ago," Professor Danforth said.

Because of the public nature of much the Internet, researchers are able to rate happiness on a much grander scale than ever before.

"What we're attempting to do is measure collective happiness on a much larger scale, similar to measuring the temperature outside," Professor Danforth said.

Your say: What is your least favourite day of the week? Why? Which words brighten your day?