On Sunday, A Gay Girl in Damascus turned out to be a married man in Scotland. On Monday, another lesbian blogger admitted that “she” was actually a male retired construction worker in Ohio. Both men wrote as women, they claimed, to be taken more seriously.

Things began to unravel for the fictional Amina Arraf, who purportedly blogged from Damascus, when someone posted on her blog that Amina had been arrested by Syrian security forces. While her supporters searched for her and petitioned the Syrian government for her release, questions started to crop up: Had anyone met the blogger IRL? That’s Internet shorthand for “in real life” — and the answer was no.

A trail of digital clues led not to Amina Arraf but to Tom MacMaster, a 40-year-old married American living in Edinburgh.

A day after MacMaster admitted to faking Amina, Bill Graber fessed up to inventing lesbian blogger Paula Brooks, the supposed editor of the Lez Get Real Web site. The admission devastated the site’s large and loyal LGBT following.

These men were lying — which is different from not being completely open about who you are on the Internet. Their extensive fictions wasted the State Department’s time, hurt online friends who trusted their stories and may have exposed the identities of anonymous bloggers in Syria. And now they are poised to claim an additional victim: anonymity online.

One Syrian writer who goes by the pseudonym Daniel Nassar wrote that now, “editors from across the globe [need] . . . to verify if I’m a real person or just another fake character like Amina; the trust between foreign media and those activists, who are needing any support they can get to continue their brave struggle, is gone forever because of Amina.”

If the revelation about Amina helps to further derail anonymity on the Web, we will wind up losing much of what makes the free and open conversation online such a powerful force. The dramatic events of the Arab Spring and the tumult still unfolding in the region have served to illustrate the need for anonymity, just as MacMaster’s deception highlights the downside.

In Amina, Western readers and journalists thought they had found a voice to explain the complicated events unfolding in Syria, much as they had looked earlier this year to bloggers in Tunisia and Egypt to provide detailed, personal accounts of the uprisings in those countries. MacMaster’s deception only added to the confusion surrounding the situation in Syria. It is a country that foreign journalists are barely able to enter, and a place where both bloggers and the government have used technology and pseudonyms to control and manipulate the news throughout the Arab Spring.

Online fakery can be truly dangerous. Judith Timson, a columnist at the Globe and Mail in Toronto, saw in MacMaster shades of a recent criminal case in Canada in which a man assumed a false name in an online chat room and encouraged a young woman to take her life — which she did. In another case, in 2006, Missouri mom Lori Drew allegedly posed as the character of a young boy who flirted with and then dumped a 13-year-old friend of Drew’s daughter. The teenage girl also committed suicide.

“Under the guise of anonymity, sick, twisted or merely mischievous people who can’t get ahead otherwise, and even just adventurous writers, can have an anonymous field day online,” Timson wrote, “wreaking relatively harmless havoc as in the case of A Gay Girl in Damascus, or finding a way to incite others to suicide or murder.”

Fake profiles are also being used by autocratic governments to spread propaganda. In Syria, authorities have been blanketing social media sites with messages purportedly written by regular citizens in support of President Bashar al-Assad.

Though there is misuse and ma­nipu­la­tion of online anonymity, the ability to speak up under a different identity — and reach a wide audience, in some cases — allows countless others the freedom to experiment without fear of retribution.

Say, for a moment, MacMaster’s and Graber’s only crime had been to pose as women writing fictional blogs. Pseudonyms have been a powerful cloak under which women have posed as men for generations. “Middlemarch,” “Jane Eyre” and even the Harry Potter books were published under masculine-sounding names (yes, even J.K. Rowling was urged by her publisher to be “J.K.,” not Joanne).

Writers — and everyone else — should be able to explore identities and beliefs online, without it being tied to our Google history forever.

“I don’t believe society understands what happens when everything is available, knowable and recorded by everyone all the time,” Eric Schmidt, Google’s former chief executive, told the Wall Street Journal in an interview last year. He suggested that the only way future generations will be able to escape their digital past will be by changing their names in adulthood. That future would be one in which every youthful indiscretion, or every opinion voiced, would be permanently recorded. No one could try, fail, learn and try again with a clean slate.

Anonymous comments, which can be a miasma of profane, inaccurate and controversial rants, are often used as the prime example of why we need more authenticity online. As bloggers for The Washington Post, we are greeted with the joys of anonymous comments every day. “Take your ignorance back to India,” “learn to read you jerk” and “what dribble” are just some of the more printable sweet nothings that anonymous commenters whisper under our posts.

Yet, at the same time, federal employees who read our work have told us that they would be unable to contribute to the intelligent debates that often take place in the comments section with their real names out of fear of losing their jobs.

Beyond the hand-wringing over this past week’s deceptions, the Web itself already imperils anonymity. While the Internet offers plenty of ways to mask identity, it also makes it easy to trace people. For instance, though MacMaster carefully covered his footprints, The Post was able to find him — on a Yahoo message board, through his I.P. address, via a dating profile and from a photograph he took from his wife’s online album.

In other cases, digital evidence has led repressive governments to clamp down on writers. A founder of the blogging movement in Iran, Hossein Derakhshan wrote extensively about his country. At his trial last year, those posts helped convict him of creating propaganda against the Islamic regime. He was sentenced to nearly 20 years in the notorious Evin prison.

Anonymity has allowed bloggers in the Middle East to safely tell the world what is happening in their countries during the Arab Spring. Anonymity allows everyone online a freedom of expression, a creativity and a breadth of discussion that might not occur if a name had to be attached.

The dangers of anonymity do not outweigh the benefits. We need to allow space for the real Gay Girls in Damascus and the genuine Lez Get Real bloggers, whoever they might be.

Melissa Bell and Elizabeth Flock, who covered the Gay Girl in Damascus blog story, write BlogPost for The Washington Post. They will be online on Monday, June 20, at 2 p.m. to chat. Submit your questions and comments now.