Unwanted Blog Creations, Spam or Delete...The Same?

Ok, here I am again, the newby question guy. I have a few questions and haven't seemed to been able to find the answers in searches, perhaps it is because the questions are so basic....

First off, if there are blogs that I want to get rid of, i.e. spam blogs, improper content etc.. if I mark them as spam it prevents them from being able to be recreated correct? If I mark them as spam is it the same as deleting them? I currently am getting the problem of the databases being to large, have over a thousand users, most are of course useless and spam type blog accounts, so I need to clean them out, if I delete them without there being some type of setting to not allow recreate the they will simply come back, how do I combat this, or is there an easier way I don't know about...an example would be lastlongerinbed.politicallygrounded.com though I am sure there have been many an arguments, divorces, fights, and out right wars caused through history over men feeling sexually inadequate, I don't relate it as a valid politically themed blog...so I deleted the blog, if you type in the blog url it allows you to obtain the blog as a new account...easy fix to prevent this would be?

Sorry for the bloviating, just frustrated at the spam and attempting to find a way to compete against it....going to have the same going on at freebloggersworld too once it is in swing but how to compete with it on an open topic blog is again another perplexing question.

Thanks in advance,
Brad