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There's been a shift in the Philbin household. At one time I fretted over what my daughter might be putting up online, but over the past couple of years the tables have turned and she began challenging me.Ìý "You’re not putting that on Twitter are you?"

I'll confess I was a bit over-keen at first, though I still think the time I caught the cat racing down the hallway with a mouse in her mouth was a triumph of photo-journalism (the mouse survived).

But it does raise serious questions. What's okay for you to share isn’t always okay for family or friends. What for you is a moment of parental pride or exasperation, your children might see as an absolute betrayal. You never know what you might inadvertently reveal. "Your skirting boards could do with a touch up" was one comment after the mouse incident.

In our digital world it's important to remember your wry remarks and cute pictures are there to be uncovered by your children's friends, their grandchildren and certainly their future employers. Digital identity expert Dave Birch draws a firm line round family life. "Our pictures of the kids, friends, vacations and the house all go on to our friends-and-family blog, which is password-protected and always has been."

When it comes to privacy, everyone has different boundaries. They're not easy to second guess and I think it's important to ask. So you might see stunning views from a walk or Wembley stadium on my Twitter stream but you won’t see who I'm with or necessarily know why I'm there.

'Documentally', a popular blogger and social media consultant, says that when he first started using social forums his profile picture was a mash-up of his face with Che Guevara because he felt his anonymity was too valuable to sacrifice. "I didn't want a face and I didn't want a name. But now I feel differently", he says. "It's only when people can see you, have a real sense of who you are, that new connections can be made. I have to be myself, not a shadowy figure. Opening up is the only way to share."

One of the hardest decisions I made recently was whether to tell my Twitter followers about my mother's death. Grief is intensely private, yet I felt odd stepping round it. After a few weeks, I wrote a very brief blog and my family was immensely touched by the warmth of the response.

Internet technologist Benjamin Ellis says he's also had some really positive benefits from revealing more about himself online, from better birthday presents to meeting new and interesting people who would never have otherwise found him. But recently he had a reminder that there were people out there who knew much more about him than he did about them or indeed about himself. "Because of my online writing, an older half-sister I have never met, who lives on the other side of the world, was able to find my father and myself when she decided to track us down".

For the most part, our social networks are benign. There are issues about bullying and it obviously makes sense not to geo-tag your home or let cyber-space know you're on holiday for a month.

What we can't predict is how, as technology moves on, people may be able to aggregate and analyse our data in ways we can't even imagine. As Benjamin Ellis says, "Modern face recognition software, combined with our online photo libraries and mobile phones that now track the location of where pictures are taken, may mean much, much more of our life becomes "discoverable" in the future." He has also set some basic rules for himself: "I never post anything if I am tired, emotional, or under the influence of too much coffee or wine!"

In a nutshell, be cautious. Don't imagine you can be protected by operating under a pseudonym, because search engines make it much easier to put two and two together. And if you share something personal or private with someone who's active in the online world, Benjamin suggests you "make it clear it’s NSFTB! (not suitable for the blog)", a term coined by marketeer Seth Godin.

But there are advantages. Dave Birch says "I'm a bit jealous of this generation: when they are my age they'll be able to look back on school, university, gap year, work, parties and weddings by going online. Whereas, it took me a week to find half-a-dozen photos from my university days for my 30-year reunion."