My topic seems to be solved by stackexchange engine but me (a human) couldn't find a solution here.
As you may understand on subject, I have many repeated words on my site like "comment", "like", "read more" and also some system messages like "mysql_result","error", "php" etc.
I saw that my most valuable words are these on Webmaster's Tools. Some people suggests to load those texts from a js file and restrict access to those files. Or using iframes for those text areas. Both have some negative sides, too.
I think about another solution which is using images instead of repeated texts but it is neither practical nor seems well.
Thank you for suggestions.