A number of WWE fans have received a new survey from the company in which they define some of their more "extreme" match types and the official rules that set them apart. Interesting they didn't list an "extreme rules" match although one could assume this is very similar in definition to a Hardcore match. 

Hardcore Match: a wrestling match where disqualifications, count-outs, and all other rules do not apply in favor of matches that take place in both unusual environments and usual environments. The use of any foreign object is allowed and these matches can occur anywhere.

No-DQ Match: match where neither wrestler can be disqualif,ied, allowing for weapons and outside interference. Falls must be made in the ring, there is less emphasis on the use of weapons, and often the Count-Out rule is still in effect.

No Holds Barred Match: match where neither wrestler can be disqualified, allowing for weapons and outside interference. Falls must be made in the ring, the Count-Out rule is not observed, and a greater emphasis on weapons.

Street Fight: uses the various elements of "No Holds Barred" and "No Disqualification" and does allow pinfalls and submissions outside of the ring. Rope breaks do not apply, so having any part of the body against the ropes will not break a submission or pin attempt.