To be able to recall exactly where a verse/verses come from in Gods Word, ie Book - chapter and verse number is fantastic, but I think that is not as important as having the Word written on your heart and mind, by this I mean that by repetitive reading of the scriptures so as to know what is written is far more important...to me it is because of this verse:
Eph 6:12 For we wrestle not against flesh and blood, but against principalities, against powers, against the rulers of the darkness of this world, against spiritual wickedness in high places.
Now when Satan comes against us and we have to draw our Spiritual Sword to cut him down, which is the Word, we don't have to say "Satan!....Isaiah 53:5 and 1Peter 2:24 says by His stripes we are healed!"
all we need to say is "Satan!...it is written, by His stripes we are healed!"
just as Jesus did when tempted by Satan in the wilderness what did He say to Satan?
Mat 4:10 Then saith Jesus unto him, Get thee hence, Satan: for it is written, Thou shalt worship the Lord thy God, and him only shalt thou serve.
there are many more examples of this in scripture
However having said that, referring to posts in these forums it is preferable to give reference to Scripture when quoting from the Word especially in the Bible discussion threads.