In Vanilla, casting a Blessing (which lasted 5 minutes) did not apply the blessing to all nearby raid members. It buffed only your target. Greater Blessings, which chaincast blessings onto all characters of the class you were casting on (so, seven casts), weren't introduced until 1.9, the AQ20/40 patch. Greater Blessings had 15 minute durations until 2.2.
It was 40 global cooldowns for your assigned blessing every five minutes up through the end of BWL.
On the bright side, addons had the ability to auto-target a player who didn't have the blessing you were casting, so...