One word Keyword ( google )

[LiGhTen]

Well, I don't know how many SEO optimize for one keyword, My question is why when I try to add links to "one keyword" example the word "HELLO" I rank lower in the SREP ?

[e10]

Keywords tend to be more competitive than keyphrases. I´ve always found it easiest to get ranked well for three word phrases, then two, then one.

[Design Agent]

Yep, I even start on 4 or 5 if it is exactly relevant. Work from the bottom up. Once you have your best 3 word niches, then go for 2 then finally 1. If you have a anchor for "buy house" it will help slightly for 'buy' and 'house' as well as 'buy house' All that work for the 3 and 2 word targeting will pay off to some degree on the 1 word. So when you finally get there its a little easier (and you should already be earning)

[T0PS3O]

And those multi-word phrases can link back to the top of the pyramid. So by expanding the base you give the top a better chance of ranking higher and higher with relevant anchor text.

[yfs1]

There is actual a really good thread about this exact subject here (http://forums.seochat.com/showthread.php?p=193685) (Just make sure to come back here to talk about it ;) )