Not sure what you mean. But when I hear the term I think of sites ranking high for a keyword that dont give the end user what they are searching for.
It's a bad idea quite simply because if you get caught, you will get BANNED. Last time I checked, getting BANNED was a bad thing. Spamming can get you some quick results and if done correctly, can make you a lot of money, but if you don't know what you're doing (which is obviously the case) it will get you BANNED. So let the experiences spammers spam and stick with white hat techniques yourself.
many sites make spam, because they require it, but if they got enough PR, and the spam words are relevant, google doesnt punish
for example you search for "flight ticket to paris" you don't realy get what you want! it's annoying, the most airline companies or big sites do that spam, they have many spam pages which you don't require, if have enoughp PR, can spam without punishment