THE world of internet dating has come a long way since the concept was introduced in the film You've Got Mail.

Pictured: Ian and Mairi Smith, who met via a dating website (see case study)

Back in 1998, the idea of the characters of Meg Ryan and Tom Hanks falling in love via email was a novelty. Fast forward and millions no longer think twice about logging on in the hope of finding romance.

There are now 1645 sites aimed at the estimated 15 million singles in the UK, ranging from the traditional matchmaking services which promise the hope of a partner for life to those offering the chance to bag a millionaire or an illicit encounter.

With the industry predicted to be worth £150 million annually in the UK by 2014, it is big business. Some companies are investing in experts to analyse "relationship science" and develop apps for mobile devices to feed the burgeoning demand for love at the click of a button.

Eight years ago TV presenter Sarah Beeny set up the site Mysinglefriend.com, where singles are "recommended" to potential love interests by friends. It began with the profiles of eight people on display – now it has nearly a million users and has recently launched in Ireland.

Beeny said internet dating was viewed very differently when she first founded the service. "When we first started, I didn't have any friends who would go on a dating website," she said. "I knew one couple who said they had met on holiday – only after knowing them for quite a long time they admitted they had actually met on a dating website. Nobody had known – it was like they had met dogging and it was really, really embarrassing."

But times have changed. Last week, an analysis by experts at Rochester University in New York found seeking love online is now the second most popular way to find a partner in the US, surpassed only by meeting through friends.

Beeny believes being introduced through friends or at an occasion, such as a wedding, is still a better way to meet a partner, but points out that internet dating can help extend social circles.

"It seems pretty logical in a way," she said. "You can wait around and hope the next pizza delivery person is hot and single or you can go and find them."

However, it is not clear exactly how easy it is to do that. Internet dating companies say pinning down exactly how many singles find love online is difficult, as people naturally leave the site once they find their perfect match.

Online matchmaking service eHarmony promotes its method of using detailed questionnaires to match compatible personalities as setting it apart from other dating websites. It has a dedicated research team of six PhD experts to study relationships and feed the results into its matching system.

The firm claims it was responsible for 5% of all marriages in the US in 2010. It says it is too early to measure the equivalent impact in the UK, where it launched three years ago, but around 60 couples a week contact them to say they have found love.

Ottokar Rosenberger, UK manager at eHarmony.co.uk, said changes in society such as moving around more and not necessarily having strong social or family networks had helped contribute to the popularity of internet dating. He added: "Online dating has mirrored the growth and importance of the internet in our lives.

"We are now used to spending much of our time online both in and out of work, and as such are comfortable with meeting and talking to new people online."

High internet usage and access to broadband have helped the industry boom in countries such as the UK and the USA, agrees Sean Wood of Edinburgh-based dating firm, Cupid plc. It was named Scotland's fastest-growing technology business last year and has more than 20 sites around the world with around 30 million users.

Wood said it was making inroads into other countries, acquiring sites in Germany and Brazil. In the UK, he predicts the use of dating apps for mobile devices such as phones and iPads will be the next big trend.

"While members are on a bus or in an office, the mobile phone is there and they will get an alert saying new people in your area have joined," Wood said.

"It is the same with social dating – for example, when you are on Facebook you can use our dating applications. They will get messages saying someone new has joined our sites in their area."

The sites owned by the firm range from "traditional" matchmaking sites such as Cupid.com to those targeted at niche markets – such as those aimed at the mature dater and single parents.

The portfolio also includes Benaughty.com, which Wood describes as being aimed at "casual" dating among 25 to 35-year-old professionals. But he denies it is encouraging any negative attitudes to relationships.

"If you arrive at a site called Benaughty.com as a dating site, it is very clear from the outset it is not the same as Cupid.com," he said. "The reality is it gets everything up front and we consider Benaughty.com to be more akin to a nightclub, if we were to compare it to an offline scenario."

For most online dating sites with a subscription service, it is free to join, to post your own details and browse other people's profiles. To then send messages usually requires signing up to membership, typically from around £20 a month. While there is clearly money to be made in modern matchmaking, is it a good way to try to seek a relationship?

In their analysis, the Rochester University scientists warned of several pitfalls, including that the emphasis on finding a perfect match may encourage an unrealistic and destructive approach to relationships.

Anne Chilton, head of professional practice for counselling at Relationships Scotland, said online dating could be successful, but cautioned it could also be a demoralising process for those waiting for that elusive "spark".

"It is relying on a different medium for attraction," she said. "Seeing photo-graphs of people is almost like flicking through a catalogue – who is it takes your fancy today?

"There is none of that immediacy of seeing someone and immediately knowing there is a spark or attraction."

Thea Newcomb, founder of Glasgow-based relationships website soyouvebeendumped.com, agrees internet dating has made it easier to meet people – but not necessarily to connect outwith the cyberworld.

"What it hasn't done is make people more compatible in real life," she said. "In that respect, for me personally, I'd rather meet someone face to face first and then they already know what I look like, sound like, seem like and I know the same about them. It saves that all-too-common awkwardness and potential disappointment on either side when the reality doesn't live up to the fantasy after you meet up for the first time."

NEWCOMB said she had tried internet dating over the past dozen years with varying success. "Ultimately I've ended up making lots of good friends but had no lasting results in terms of romantic relationships," she added.

Professor Monica Whitty, a psychologist at University of Leicester, said there are many positives to internet dating but one difficulty was that people become "commodified" in the cyberworld. "You are being treated like a commodity that is being shopped for in many ways," she said. "So people turn up to their first date and if they have embellished the truth in some way and they don't live up to their profile, then they are just dismissed very quickly as well. The first outing is not really a date, it is more a meeting to check out if they have fitted up to their profile."

And while a little exaggeration on a profile may lead to an awkward meeting, there's also the possibility of a much darker side to the ease of lying online. Last year, research by Whitty into romance scams suggested there had been 230,000 victims in the UK, involving criminals using fake profiles to woo unsuspecting targets online with the intention of conning money out of them.

Whitty said the scam preyed upon the type of "hyper-personal" relationships that develop online, in which people get very close and disclose large amounts of information about themselves.

"For those I have interviewed, the loss of the relationship is seen as just as traumatic as the loss of money," she said. "One of the bizarre consequences of this scam is they just find it so difficult to believe. Even years later some of them can't see in their mind that it was a criminal - writing to them."

But another surprising finding, Whitty said, was those who had fallen prey to a cruel deception were not necessarily deterred from trying to seek love online.

"They still find there is some benefit of online dating. They don't want to give up."

Case study: true love bytes

WHEN Mairi Smith, from Edinburgh, joined dating website Match.com in February 2007 aged 26, she says there was still of “a bit of stigma” to internet dating. But she decided to try online dating in an attempt to expand her social life, without intending to take it too seriously.

The profile of Iain was one of the first she came across on match.com, with his love of motorbikes catching her attention. Four months after meeting they moved in together and are now married, with a three-year-old daughter, Amelie.

Mairi, now 31 and training to be a psychotherapist, said: “It was along the lines of nothing ventured, nothing gained. I was fed up going out to bars, as I never met anyone that I would like.

“I went to university in Edinburgh and had left and come back. A lot of my friends had moved on, so it wasn’t the same social life. I was thinking, how am I going to meet someone I actually like?”

She added: “There is definitely less stigma around internet dating than when I started. People’s lives are so busy and it is not always easy to just go out and meet people the traditional way.”

Fiona Burns, 44, and Mark Dobson, 45, from Kirkcaldy, Fife, met via the site eHarmony.co.uk in September 2010 and will get married this October.

Dobson, a self-employed landscaper, said he tried other sites and decided to make one last attempt at internet dating. He was matched with Burns after two weeks.

“My mates were all married with kids and I didn’t get much chance to get out, so internet dating was the only option really,” he said. “I’ve recommended it to some of my friends as well.”