KEY POINTS:
They've only started arriving in the last few months - invitations from friends to join their social networking circles on Bebo, Facebook or MySpace.
As a result, I've now got accounts on all three services as well as Flickr the photo-sharing website. Long perceived as the domain of teenagers or college students, these social networking sites seem recently to have hooked a more mature audience - other "adults" I talk to have also noticed the sudden proliferation of invitations turning up in their email inboxes.
So what's driving it? The increasing awareness of Bebo and Facebook as alternatives to the youthful gaudiness of MySpace is one factor. The other thing seems to be the growing realisation among people of how useful these services are for storing and sharing photographs. It is something everyone can relate to.
I must have looked at a dozen sets of holiday photos uploaded to the internet by friends and colleagues in the last few months. The ability to present a digital photo album online and restrict access to it has been around for years, but only now seems to have caught the imagination of the average computer user aged above 20.
MySpace is still the most popular of around 300 social networking websites of its kind, but is losing ground in its key US market - visits to the website dipped to 56.7 million in May compared to 57 million in the previous month, says ratings company Nielsen.
Facebook could catch up with MySpace in the US this year if its growth continues at the current rate. In New Zealand Bebo has a particularly strong following.
But research from Britain would suggest that I'm typical of those signing up to these social networking websites - I have no loyalty to one particular network. Most of the services are free to join so there's nothing to stop us hedging our bets and linking up with networks that span different providers.
A survey of internet users by analyst group Park Associates found that people who use social networking websites are "chronically unfaithful" - half of them use more than one site, one in six use three or more.
Facebook is my favourite of the top three, probably because it is more adult-like. Its users are less inclined to "pimp up" their homepages like Myspace users are and tend to participate in closed networks, giving out only basic information for public digestion. I'm more comfortable with that approach, especially given some of the horror stories we're continuing to hear about the dodgy elements of social networking.
TV3's 60 Minutes programme this week told the story of 14-year-old New Zealand schoolgirl Sophie, who became infatuated with her online friend Ben, the pro-surfer she met on Bebo. Sophie never met Ben in person and when told by another Bebo friend that Ben had killed himself, Sophie attempted to take her own life.
It turns out that Ben probably never existed - the figment of someone's twisted imagination complete with fake photos and profile.
Some schools are considering banning the use of Bebo on school computers because the network is being used by students to mock and bully classmates.
In the Canadian documentary Cybersex Addiction we heard the desperate story of Allan, the 56-year-old lawyer who had a normal life until 1999 when the company he worked for connected his office to the internet.
"Within two or three weeks, I was grossly addicted to internet porn. It just wreaked havoc with my working life," said Allan, who had to seek treatment after spending most if his time having lewd chat sessions with strangers.
Nicole, also featured in Cybersex Addiction, went one better. Completely detached from reality in her little network of cybersex partners she swallowed a bottle of Xanax tablets one night and said her goodbyes to her chat buddies as she slipped away. Luckily someone in her network called the police, saving her life.
"They found me in my skanky webcam outfit," said Nicole.
Then we've got the British youths in Kent who are using Bebo and Facebook to organise after-school fight clubs and the 140 sex offenders convicted in New Jersey who were discovered to have MySpace accounts. That's just one week's worth of social networking news. It's no wonder I get a little paranoid when emails like this one keep turning up in my inbox: "Elina would like to be added to your MySpace friends list."
I've no idea who Elina is, but her profile makes her look like a Playboy bunny. I'd hate to share the same fate as Allan, Sophie or Nicole so I won't be social networking with Playboy bunnies- unless I've met them in the real world first.
