Blood elves are high elves who, after the Scourge invasion of their kingdom, changed their names to blood elves to reflect both their royal lineage and the loss of life they suffered because of this invasion.
During the invasion the Sunwell, a source of power the blood elves relied upon and became dependent on, was corrupted, and their prince, Kael'thas Sunstrider, vowed to find a cure for this dependency. While Kael'thas ultimately failed, the Sunwell was restored eventually by Velen, the draenei prophet, using energy of a darkened Naaru.
The blood elf language (Thalassian) is closely related to that of the night elves (Darnassian), but their names are often quite different, with the exception that both often roll off of your tongue quite easily. Blood elf names tend to be harsher though.
Despite their painful past, Blood Elves still use the same traditions when it comes to naming their children. Names of Blood Elf champions, priests, and other important elves from the past are now used as a name for their newborn.