What is the queue position? I have an unconfirmed transaction. (As an experiment, I didn't add a transaction fee, and the transaction is taking a lot of time to confirm.) This is some information from blockchain.info regarding the transaction:



The info "queue position 427" caught my eye. What exactly is the queue position?
It is most likely (blockchain may figure this out differently) the priority of the transaction compared to others. Nodes add highest priority transaction and repeat until they reach the block size limit. 

https://en.bitcoin.it/wiki/Transaction_fees

priority = sum(input_value_in_base_units * input_age)/size_in_bytes