Search engines are confusing! Even the best search engine optimisation professionals have messed up at times, but of course there's nothing like learning the hard way. Unfortunately, your clients aren't as forgiving as you may be to yourself. So here's a list of some of the worst mistakes an SEO company can make. Hopefully, you'll be luckier than the guys who burned their fingers and gave us these lessons to learn from.

#1 Poor keyword selection
Choosing the wrong keyword is common, but there can be some really poor choices. Most popular terms are very often dominated by links to sites whose rankings that are immovable and unshakable, namely Wikipedia, Amazon and About.com. Be realistic in selecting keywords because there are some terms that not even the best SEO can breach.

#2 The same title tag
The oldest mistake that SEO firms make is using the same title tag, usually with the name of your company in it, on EVERY page of your website. If your company name is unique, you'll rank well enough for it anyway. When creating a new page or adding extra content, the title tag plays a pivotal role in directing visitors to this information.

#3 Uncrawlable websites
There are tons of reasons a website may be rendered uncrawlable. A bad robots.txt file can send Google's spiders scurrying away, too much flash can render it "unindexable" and dynamic session ids can make your pages expire taking away valuable Page Rank. Too many variables in your internal links as well as those tricky convoluted menus can also be roadblocks for the web crawlers. Keep track of the spiders as they make their way through your pages.

#4 Ignoring Content Creation
The only way to keep up in the online marketing world is to constantly add value to your website. Creating unique content is the key to building a long term online presence. The only guarantee of consistent traffic is new, interesting offerings in terms of products, service and this is driven by good content.

#5 Considering SEO complete
A laughable and yet immensely popular notion is that the SEO firm is done with its optimisation on a website. Worse still, is the belief that the web design team put together your SEO plans. Keyword popularity, search engine policies constantly change. So any website owners that believe their SEO is "done" are sadly mistaken. The SEO strategy is a long term marketing plan which must work in an ever changing playing field, that is, the Internet.