SEO optimization

I understood from a search engine optimization company that a website I built must do something terribly wrong because looking for the two words in the domain name does not result Google in showing it on top.

1. I have not tried to market the website (which may be part of the problem, but not a hindrance)[/*:m:35d7qz0h]
2. The site uses pure HTML + CSS, no confusing tags[/*:m:35d7qz0h]
3. Contents are original[/*:m:35d7qz0h]

So what could be the problem, is there something Contao might be doing wrong.

The website is: http://easy-banners.nl

You absolutely HAVE to provide page descriptions in the Site Structure. Also, for Home pages, or any pages really, I generally add a page title that is more descriptive than just HOME. Also, if you change the page Title of the site structure ROOT point, that will be used in the website title as well, eg.

Setting up a different page title for the HOME page:
-- Home (page name)
-- home.html (alias)
-- Quick and fast Banners, Flyers, Brochures and B-Cards (page Title)

Setting up a different page title for the SITE ROOT:
-- Easy Banners (page name)
-- root.html (alias)
-- Easy Banners - Any Banner Shop (page Title)

Then the standard template will render as the HOME page title, combining it with the SITE ROOT page title
[home title=Easy Banners, Flyers, Brochures and B-Cards] + [root title=Easy Banners Company - Any Banner Shop]
Final Result >> Easy Banners, Flyers, Brochures and B-Cards - Easy Banners Company - Any Banner Shop

The description together with the revised page title are the two most important keyword sources I've found for search engines. If you omit the page description, you are penalized.

You can add keywords too in the Articles areas, however Google relies less on keywords (I think leo will be removing it from the core).

Thanks for your hints, I've updated the website with the said additions. I guess in about three months we will see the improvements. Although your instructions were very clear, could you check if I did what you meant?

Why would Leo remove the keywords section? It may be a less used element right now for Google, but that doesn't render it useless or even a close to a section that could be a candidate for removal. Contao should concentrate on the HTML spec, not Google (Google at this moment in time).

try this firefox extension ;)
https://addons.mozilla.org/en-US/firefox/addon/senseo/

There are extensions in Wordpress for SEO, and they go way beyond the normal SEO in Contao. These check a focus keyword (one keyword for a page or post) and this keyword should appear in the TITLE, ALIAS (permalink), DESCRIPTION, Keywords (optional), H1-H3 and in the body several times. This ensures that the page or post has been written with that keyword hitting the top spot.