Hi Astrid,
Well done great article there are a few points I would argue about with what you said (nothing was incorrect) and as you said the rules are not set in stone.
Your English was great and easy to read I am an Englishman so can comment on it.:-)
Its great to see someone young and with fresh ideas getting into the internet marketing world and using Professionelle Suchmaschinenoptimierung is a great way to start.
I see you mentioned Googles youtube search tool,there is a better one about which I use and that is TUBE EQUALIZER naturally you have to pay for it but it speeds up the whole process and works here in Germany perfectly.
I’d love to have a one on one chat with you sometime if you drop me a mail on the above email address I can give you my skype name or phone number.
Its no problem for me if you write in German if that is easier for you.
Wishing you all the best PeterB