So have you been poked by a pupil yet? Or held up to ridicule in the school corridor for those terrible drunken photographs of you, and what on earth were you thinking allowing all those crazy messages to become public? Catching up with the gossip, being nosy about how old friends are doing and making plans for the weekend are all very well. But when teachers lay their life bare on the internet, they can find themselves in trouble.
Teachers, unlike many other professions, face huge dilemmas when signing up to Facebook, the worldwide social networking phenomenon that claims an incredible 150,000 new members every day.
Sharing their laughter and tears, the whole point of Facebook, can lead to a loss of face and control in the classroom. Or it may allow friendships with ex-pupils and lead to the kind of feedback that makes the job worthwhile.
Research from America suggests that some pupils bond better with their school staff after reading about them on Facebook and already many teachers are more open about themselves in the classroom.
Pupils at Samantha Lunn's school in Blackpool tracked down the 25-year-old French and Spanish teacher even though she had signed up to Facebook to avoid the more limited privacy controls of the teen-infested Myspace.
At first Samantha, who teaches at Arnold School, panicked, but then she started to question just how important the information was she had on her pages. That she lived in Preston wasn't exactly big news to anyone at her independent school, and showing her pupils that she had a life might have a positive spin off in the classroom.
Samantha decided to add only upper sixth pupils that she has a positive relationship with to her Facebook list of friends but even then they only have limited view. After all, chatting to pupils on Facebook shouldn't be any different from chatting at the school ball, she believes. It's just the virtual-ness that's getting everyone confused.
"Teachers have the right to be active in the virtual world just as much as in the real world, but like the real world they have to take care how they behave in public.
"I don't have many drunken photos or crazy messages on there anyway, but if I wanted to keep something private I would just send a message privately, or ring or talk to someone in person. Not everything has to be done virtually."
Esther Slater, a 27-year-old PE teacher in Kings Norton High, a Birmingham comprehensive, joined Facebook a few months after friends introduced her to the site. "I didn't realise that there were any problems with Facebook until another teacher at my school poked me," she says.
Poking, not some medieval torture but an electronic greeting from one Facebook member to another, is an everyday occurrence for millions of people.
Esther had used her Facebook site just like most of her friends, for catching up with each other. She hadn't realised that her pupils might be able to see her musings too.
"I asked him how he could find me when I'm not a friend, and he told me that my privacy settings weren't high enough. That's when I realised that I had to set my profile to private." But should schools encourage teachers to allow pupils to be Facebook friends? One teacher, who didn't want to be named, told The TES Magazine that she felt almost bullied into adding sixth formers' names by the number of colleagues who had already added pupils to their Facebook profiles or websites.
But she said was pleased when the sixth formers started using it as a way of asking questions about that day's lesson or the week's homework. She drew the line at under 16s, for fear of the paedophile tag. Her school has since banned teachers from having current pupils as Facebook friends, along with any photos of pupils or school events.
Research from the United States (by Mazer, Murphy and Simonds, published in Communication Education in January) suggests that older pupils may be more motivated by chatting with teachers on Facebook because of the bond that develops and the almost instant feedback to their questions outside of class.
Other pupils who were surveyed said that they were worried about interacting with their teachers in such a social context and about their own privacy. One teacher interviewed for this article did admit to spying on one pupil's message board to see if he really had been ill when he was absent.
Chris Keates, general secretary of the NASUWT teachers' union, says that teachers especially the younger ones who tend to use Facebook need to be extremely cautious compared with other professions.
She says there is always the potential that the sites will be accessed by their pupils and the information misused, with little opportunity for redress if the worst does happen. "The misuse of internet sites is causing untold distress to many teachers," she says. "Pupils who once had to content themselves with exhibiting poor behaviour when face to face with the teacher, now increasingly use the internet to support their indiscipline."
The union is dealing with the case of a pupil who posed as a teacher and then invited his contacts to become friends on the fake profile, gaining access to details of hospital visits and other information. Other pupils were then encouraged to log on and see the results.
Today, teachers such as Esther are more careful about what they post. She has new privacy controls as she doesn't want to lose her pupils' respect and says: "Some girls have pictures of themselves in bikinis. There are some dodgy photos of me that I won't put up. Whether that's because I'm a teacher, or because I'm me, I don't know. *
What is Facebook?
* Facebook is a worldwide networking phenomenon, with a slightly older and more professional membership than its rival Myspace, which is owned by Rupert Murdoch. * Each member has their own profile or website on Facebook, which their Facebook friends can see. They can post messages, photos or clips on each others' message board or wall. * Members then fine tune their privacy settings, which controls how much of their profile non-friends and even friends see if, for example, they post a message. * Poking is the electronic equivalent of a tap on the shoulder, or an electronic greeting.
The other side of Facebook
Those caught up in the Virginia Tech shootings in America in April found out the hard way how little control they have over their postings when the media trawled through their profiles for personal details after the massacre.
After all, even replying to a poke or joining a Facebook group can allow others to see your profile, and depending on your friends' settings, others who are not-so-friendly will be able to see your posts on your friends' walls.
Last week Facebook announced it would open its member list to internet search engines. The move means names and profile pictures will be available to non members for the first time, raising fears that it could compromise the privacy that has been one of the reasons behind the site's popularity.
Ru Breese, 25, who has just started an English PGCE at Manchester University after a successful career in the media, feels that teachers aren't the only ones having to worry about Facebook disclosures.
"Working in the media industry, I did not want potential employees, clients and suppliers or colleagues to see me posting distasteful comments on friends' walls, using bad language or displaying my life history and domestic dilemmas on my profile," she says.
"Facebook is a wonderful way to network, make new friends, and dig out old ones," says Ru, who has set up a self-help site for student teachers on Facebook (www.facebook.comgroup.php?gid=2486960038)
"It's fun and a simple site to use and should be seen as a tool to help you in your career as well as boosting your social life."
1. Have a neutral picture of yourself as your profile image.
2. Look at your privacy settings before you post.
3. Don't post embarrassing material.
4. Be careful when replying to pokes or joining groups.
5. Use a pseudonym as a disguise.
6. Choose your Facebook friends carefully and ask about their privacy controls.
7. Don't have pupils as Facebook friends.
8. Remember former pupils often have friends still at school.
9. Have a separate site on Myspace for them.
10. If in doubt, don't post, phone.