Thanks Joel and Richard for your answers.
You make me wondering whether my strategy is good.
Here is the strategy : I have a website about proofreading service in wordpress. I have other domains whose name are my critical keywords. I was planning to copy/paste my main website on the secondary sites and obviously to change the content to avoid duplicate content (but wordpress template and design will be exactly the same on all the sites).
Once this is done I was planning to link the websites together.
Is there any risk of being classified ''black hat'' by Google ?
Thanks a lot,
Dan