I refer to the publishing of any website I might create via your website maker 5. - I would like to include on the website, my own keyboard arrangements of various popular songs. many of which would not yet be 'out; of copyright. Which I believe is 70yrs. ?
Because these are my arrangements and my playing, does it give me the right to publish them on my website. ?
First of all, even though MAGIX supports this website, this is a USER's forum. If you want to ask MAGIX a question, you'll have to contact them directly.
According to US copyright law, any work created after Jan 1st, 1978 is protected 70 years after the death of the copyright holder! You can read the basics of the copyright laws here...
http://www.copyright.gov/circs/circ1.pdf
By playing your own arrangement of a piece, you "may" avoid paying royalties to the original artist(s), HOWEVER you will still owe them to the composer (who may be the artist as well).
For website licensing, you can start your research here...