bit is 0 or 1.
It is Bitcoin. (not Bit coin)
What is the purpose of this thread, exactly?
It is bitcoin (without a capital letter) to label units of the currency and with a capital B otherwise.
Since Bitcoin is both a currency and a protocol, capitalization can be confusing. Accepted practice is to use Bitcoin (singular with an upper case letter B) to label the protocol, software, and community, and bitcoins (with a lower case b) to label units of the currency.
https://en.bitcoin.it/wiki/Introduction#Capitalization_.2F_Nomenclature