A blitz is a play where a defender (linebacker or defensive back) attempts to cross the line of scrimmage when they normally would not.
So any attempt by a linebacker to pass the line of scrimmage (LOS) is normally considered a blitz; HOWEVER, when the LB lines up in a 3-point... whether he is a linebacker or not... once he gets into that 3-point, he's thought of as an end being played by a linebacker that is rushing the quarterback... not as a linebacker who is blitzing.
To be honest, a lot of people see that 3-point as optional too these days... if the LB lines up AT the LOSin an obvious passing situation, he's generally considered a rusher, not a blitzer... but I think that much is open to personal interpretation.
Blitzes are usually actually defense calls too. The formation and responsibilities throughout account for someone who wouldn't normally try to cross the LOS, trying to do so. On any given play, the guys lined up on the LOS are expected to 'rush' the passer... any other player on the field is blitzing.
But Gregg Williams has said HIMSELF that they have NOT been blitzing because of the secondary play. I'm not really sure why we're arguing whether they have or not when the DC hiomself has stated several times that he is not, and what his reasons were for not doing so.
Wax poetic about whether or not they SHOULD, or about the results of what not doing so are, but I think when you have it from the horse's mouth that they haven't been blitzing... it's safe to say that they haven't been calling many designed blitzes.
Sure there are plays scattered throughout where thy do, but for all intents and purposes, this is a shell of the aggressive defenses that Gregg williams has put forth in the recent past... both in aggression through the blitz, and unfortunately, in the results as well.
Sean Taylor was one of a kind, may he rest in peace.