In pondering a non-evil Drow play through, I found myself wondering what the term "Lolth-sworn" actually means. Do all Drow go through some kind of initiation ceremony whereby they formally swear fealty to Lolth? Or are all Drow, um...'baptized' at birth and 'opted-in' to Lolth worship? Is it just about worshiping Lolth, rather than some kind of formal vow to the Spider Queen?
But the impression I get of this racial differentiation is that it is really determined by whether or not the character formally participates in Drow society. A Seldarine Drow basically seems to be any drow who doesn't participate, or rejects, traditional Underdark Drow society. Good, evil or neutral, Seldarine Drow don't seem to follow the standards and values of Drow society, rather than being someone who isn't formally 'sworn' to Lolth.
In researching this question, I've run across some different kinds of Seldarine Drow. In Faerun lore, such Drow have usually been outcasts from Drow cities (the most famous of which has been Drizzt Do'Urden, of whom I actually don't know much about.) But apparently there are some Drow who did not opt to follow Lolth into the Underdark (search for 'Aevendrow'.) This seems to be a fairly new concept recently introduced by Wizards of the Coast.
As a point of reference, most of my knowledge of Drow comes from Greyhawk not Forgotten Realms. Drow cities in Greyhawk are more chaotic and less racist than Menzoberranzan, but still quite evil. Or at least Erelhei-Cinlu seems rather different.
