Wikipedia tells me that “Six is the second smallest composite number divisors being 1, 2 and 3. Since six equals the sum of these proper divisors, six is the smallest perfect number.” [Link]
The number of strings on a standard guitar is six. The beehive is six sided. The number of carbon atoms in benzene ring is six and so also atomic number of carbon.
There is something special about the number six. It generates a lot of energy and gives an “Aha” feeling! Just recall what happens when a [cricket] batsman hits a six! The entire stadium gets on their feet and applauds!!
The bloggers first met on 20/12/2008 which also adds to six. But the bloggers were only five in number. So they made efforts to get one more in their group, invited six more to join, one accepted [five were far away in blogosphere] to make the group of six!
So they promptly expanded the group to six by organising a bloggers’ meet over lunch.