No offence intended, but there are 10 (*) kinds of people: One that understands binary, and one that doesn't ;)
I'm afraid that I have to correct you with more BOF stuff:
One Byte (= 8 bit) in a binary system can represent 2 to the power of 8 = 256 different numbers. The first one, 00000000, is zero, so the highest number of one Byte is 256-1 = 255 (11111111) - sic!
Regarding the friends list, it means that at least one vector or array index in the system has only one Byte capacity, it can only count (and point) to 255 different storage places, omitting #zero. Others must have more (probably two Bytes), to hold a bigger list. (Some have 4,000 friends, some have more as we heard).
BTW: Two Bytes have a capacity of 65,536 different states (256*256 or 2**16).
BTW2: Hexadecimal coding puts 16 states in one digit, so the count above 9 continues with A to F. Four bits are necessary.
Examples: F (hex) would be 15 (decimal), 10 (hex) = 16 (decimal). FF would be equivalent to 255 in decimals.
(*) In binary representation, the (decimal) number one is 01, two is 10