Engage in any behaviors that will intentionally harm a client or a competitor. This includes performing black−hat techniques that may get that client’s site banned from the search engines, or purposefully interfering with a competitor’s site as to try and get their site dropped from the search engine in order to get their client’s website into a better position.

Intentionally engage in activities in direct violation of a search engine’s guidelines. Again, these types of behaviors can impose penalties by search engines, or banning from the search engine indexes altogether.

Purposefully engage in behavior that breaches a client’s confidentiality or privacy. An SEO many times has access to your sensitive materials on your website, including documents, logins, passwords, product information and other items. It is not acceptable for an SEO to make this information public, nor is it acceptable for the SEO to discuss your account with other SEOs that are not particularly working on your account.

Deliberately violate any laws, including but not limited to trademark or copyright laws. SEO’s that use copyrighted names, like Google or PayPal or Sony or even misspellings of trademarked names, in order to inflate a site’s ranking is considered illegal, and punishable by law. It won’t be the SEO in trouble, but rather you and your site will take the fall. Make sure there is a clause in your contract that addresses this issue.

Falsely claim another’s work to be their own. SEOs sometimes do this in order to make their portfolio look impressive, especially when they know a client probably can’t or won’t follow up on their portfolio examples. It is a good idea to ask the SEO for specific references, and outline the exact work that was done for the client, and ask for permission to contact that client to corroborate the SEO’s claims.

Intentionally mislead, harm, or offend a consumer. This includes bait and switch tactics intent on bringing traffics to the site, or making a visitor believe the site is something it is not. An example of this is to use terms like “Disney” or “Teddy Bear” in order to get a visitor to come to their website, when in actuality it is an illegal wares site or a porn site.

Disparage other SEO consultant, SEO companies, or former and current clients in public, even if you know they have engaged in unethical techniques, or treated the SEO badly. It is never professional for an SEO to bad−mouth another SEO or SEO company to you or anyone else. It’s just bad business practices, and should make you wonder if the SEO will talk about you in the same way.

Fail to stay current on search engine updates, changes, news, training or education. It is in your best interest that your SEO know what’s going on today in the search engine world, due to the fluid nature of search engine changes which occur very frequently.

Set unreasonable expectations for success, including providing iron−clad guarantees that cannot possibly be reached or maintained, timetables that cannot be met, etc. As much as anyone would like to believe, there is no one that can guarantee you number one results in a search engine results pages. If they do, save your money, and then run the other way really fast!

Make promises that cannot be kept. Well, we are all probably guilty of this one, and while no one can always keep a promise, in the area of SEO, you will have to know what promises can be made, and which cannot.

Encourage a conflict of interest between two clients’ sites which pertain to the same keywords without notifying both parties of the conflict. This is a tough one, and many SEO experts debate this issue. While it is highly unlikely the SEO will be optimizing sites for exactly all the same keywords and phrases, companies certainly can have this problem, as sites in competitive industries such as travel and computer software are all competing for the same keywords. It’s not ethical of your SEO to cross optimize sites that will be competing directly against each other. Some SEOs believe this is okay, as long as both clients are informed. This is a gray area, really, but ultimately it is up to you as the client to decide if this is an acceptable practice.