For years LinkedIn has been derided as the poor cousin of the social media family. The dull professional networking site struggled to hold its own against its sexier relatives, Instagram, Facebook and Twitter.
But last week it was thrust into the spotlight in the UK when the 27-year-old human rights lawyer Charlotte Proudman posted a screengrab of a 'complimentary' message from an older married lawyer, Alexander Carter-Silk.
While that incident went viral - with the whole world apparently debating whether Proudman was a ''fearless feminist'' or ''man-hating feminazi'' when she called him out for being sexist and inappropriate - a week later we are still asking: what are the new social networking rules?
Rules of engagement
LinkedIn launched in May 2003 and now boasts more than 300 million members in 200 countries. It has replaced the old channels of a drink after work and friend-who-knows-a-friend, to become what Forbes magazine calls "the most advantageous social networking tool available to job-seekers and business professionals today".
"Ultimately, we're focused on making professionals more productive and successful,'' says Danielle Restivo, senior manager of global communications at LinkedIn. ''My job is to help professionals better create a strong profile, find new career opportunities and use networking online to their advantage."
LinkedIn devotees are evangelical about how empowering this tool can be - particularly to young employees, women, or anyone who might feel excluded from the boozy, cliquey ''old boys' club'' of conventional networking frameworks. "I can't imagine life before LinkedIn and Twitter," says a long-time user, a charity fundraiser. "You can't always rely on supportive colleagues to notice what you're good at, connect you to important people and put you forward for things. In 2015, you have to do it yourself."
Unwanted side effect
The popularity of the site - specifically with young, ambitious and image-savvy women - however, has led to an unwanted side effect: men trawling the site, sending solicitous messages, all under the respectable, besuited guise of ''professional networking''.
"It's got to the stage where every time I see a male profile in my inbox, I assume it's going to be someone commenting on my 'minxy' photo, rather than a genuine professional invitation to connect," says one disillusioned user.
For women on the receiving end, this has been a bitter pill to swallow. LinkedIn sold itself on the promise of new-generation networking, a level playing field and an opportunity for ambitious professionals, regardless of race, gender or geographical location.
The trouble is that humans often behave worse online than in person. Occupational psychologist Alan Redman, of the consultancy criterionpartnership.co.uk, explains: ''Online behaviour encourages a process psychologists call de-individuation, where we see people indulging in behaviours that are more extreme, impulsive and unrestrained than normal.
"We will go further in an email than we would if we were confronting someone face to face," he says.
But LinkedIn is now pledging to tackle that. "The 19 million UK members on LinkedIn are there to become better professionals," says spokesman Darain Faraz. "The online world has no shortage of places for people looking for dates; and if someone insists on trying, we have tools in place to block them and even remove them from the site."
How to be a savvy social media networker
Keep it professional: Write every message as if it could be screengrabbed and sent to your boss, partner, child - or the world, whatever is scariest.
Avoid being a work cliche: Don't use words like "motivated", "creative", or "enthusiastic" to describe yourself, advises LinkedIn's Danielle Restivo. Ditto ''passionate''.
Get involved: Join groups, and post articles you feel qualified to expound upon. "A few simple 'likes' and 'shares' will quickly show your connections the things that matter to you."
Don't be a fair-weather friend: "Be active, even if you're not actively searching for a job," says Restivo. "It's a great place to meet people who may be of help to you even five or 10 years from now."
The Telegraph, London