Hypenated domain names have always been regarded as good search engine fodder. The "-" is somewhat invisible to Googlebot.
Do a search for an underscore and then a hypen and you will see that the hypen shows no results and the underscore shows millions.
http://www.google.com/search?hl=en&l...=Google+Search
http://www.google.com/search?hl=en&l...8&oe=UTF-8&q=-
Problem is that spammers buy up a lot of hypenated domains and place no real content on them so their Google life expectancy is limited.
big-sex-porn.com isolates the keywords better than bigsexporn.com which could be confused with "bigs exporn".
Question 2 is a can of worms.
