College of mine pointed a blog post to me written by Peter Kent, author, SEO for Dummies. The post claims that 80% of search engine marketing consultants are scammers and I must say that I agree. I have seen some poor samples of SEO consultancy to even the biggest companies.
In the post there is also a mention of flash designed webs having poor visability, even though I have seen search optimized flash sites they tend to have lesser chance than other and I must also say that I agree with Peter when he claims not having seen evidence showing that flash sites are indexable, I have but for me it’s rather a question of the ranking.
The rule is that you do not hire anyone that says he/she can get to the top 10, even if he has done it for another client, different clients have different needs.
Another thing is be carefull of what tools you use, many are just there to collect information about you and your activities, understand trends and so on.
Get case studies and references to verify that they are correct.