Let me answer obliquely by saying that yes I have paid some money and it worked in terms of increasing my keyword results but it didn't pay off in terms of expense to get there. There are some that did precisely what they promised but I anticipated better revenue for the results that did not pan out. So I would just caution you to make sure it is worth the expense. Professional SEO is not cheap. The fundamentals are pretty common knowledge about keyword optimization, density, etc and there are free tools and discussion at seochat.com to do it yourself. What you're paying for are some "tricks" and other things that will cost you some money to sustain so make sure you can bankroll that before you commit.
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