So, how many Facebook friends is too many?
At last, the news that all of us with, ahem, minimalist social circles have been waiting for. There's now scientific proof that Facebook users with several hundred friends are in fact saddos.
According to Robin Dunbar, professor of evolutionary anthropology at Oxford University, the ideal number of Facebook friends is 150; no more, no less.
Dunbar believes that the human brain simply can't cope with 151 friends, never mind the several hundred that some Facebook users believe themselves to have.
The magic number of 150 is now known as Dunbar's number. In his latest book, How many friends does one person need?, he points out how often the number 150 crops up throughout history.
For example, companies in Roman armies comprised 150 men, the average population of a medieval village was also about 150, and when the Mormons set off to found Salt Lake City in the middle of the 19th century, they did so in groups of 150 at a time.
Even today we can't get away from it, as smaller societies are grouped around this magic number. In the Amish community in North America, parishes consist of around 150 people. Closer to home, apparently the average person sends Christmas cards to 150 people, although the number of households maybe less.
Why? Well it all goes back to monkeys, as these things often do. Several years ago, scientists discovered that the size of a monkey's brain determined the size of the groups they formed. Monkeys with bigger brains formed bigger communities. The average monkey lives with a group of about 50 other monkeys.
It was only a matter of time before someone decided to apply the same theory to humans. According to the size of our brains, we socialise in groups of 150.
Of course, Dunbar is quick to point out that this circle of 150 friends is actually made up of smaller circles. At the very centre there are actually only a handful of people with whom we are intimately involved. Around this inner circle are groups we deal with on a regular basis -- extended family members, work colleagues, neighbours, people from our painting class and such like.
Our overall circle may even include the local shopkeeper or the postman, depending on how regularly we see them.
The important point is that the group will never exceed 150 people. Anyone outside that group is just a name or a vaguely familiar face. It's not that we're mean -- it's just that our brains simply can't handle any more than 150 connections.
According to Dunbar's research, family members make up a significant part of our social circle, especially for people who come from large extended families. These people tend to have fewer friends. Part of the reason for this, says Dunbar, is that if we don't actively keep up with friends, they grow distant. Whereas no matter what we do, we're generally stuck with our families. So they continue to feature in our 150-strong social circle over many years, even if we don't see them much.
Dunbar also suggests that some friendships can remain buried in our minds. With the advent of Facebook, lots of people have rekindled friendships with old school and college chums. Facebook has also reconnected people with old flames and in some instances affairs have reignited, suggesting that people can remain part of a social circle, in our minds if not in our physical lives.
But what of those Facebook users who have more than 150 friends? Are their brains in danger of exploding from having all those connections?
Marie Boran is editor of Gadget Republic and, at 300 Facebook friends, has double the recommended number according to Dunbar.
She is surprisingly aware that these aren't all friends. About half are work connections. Some aren't even people but technology companies that operate a Facebook page.
"I use it as an online address book, to be honest. I never use the chat function because I don't really want to chat to these people and I'm sure they don't really want to chat to me. It's just a convenient way of keeping in contact and exchanging information when necessary," she says.
And that seems to be the problem with Dunbar's theory as it applies to Facebook. He doesn't use Facebook and perhaps that explains why he assumes that Facebook users can't tell the difference between their Facebook friends and real-life friends.
Granted, these groups sometimes overlap but most of us have close relationships with people who aren't on Facebook and are never likely to join.
People in the public eye also use Facebook as a way of connecting with their fans. Barack Obama has 7.5 million fans on Facebook. It's safe to assume he doesn't actually believe these are close personal friends.
As Boran points out, perhaps the professor of evolutionary anthropology isn't quite so up to date on the evolution of Facebook as he might like to think.
That said, his theory does raise an interesting point about the purpose of Facebook. Is it an online contact book for work-purposes or a way of maintaining friendships?
"I suppose many of us are still confused about this," says Boran. "I put up pictures on Facebook recently of messing around in the snow with friends. I'm sure most of my contacts had no interest in them whatsoever. I think the whole Facebook thing is still evolving."
In the meantime, there's a new group on Facebook asking: 'Have professors of evolutionary anthropology at Oxford nothing better to do than write books about the number of Facebook friends we should have?'"