My content does not consist of videos, tutorials etc., but of a MySQL database which members can search through a simple form. Can I use amember for this purpose or will the two MySQL databases (my own and that of the amamber install) obstruct each other?
Yes. A couple of easy ways to accomplish this with aMember: 1) Protect the folder that your "simple form" runs from. When users try to access it they will be prompted to purchase or login. 2) Using the PHP include protection option which allows you to add a line of code to the top of your "simple form" to protect the execution of the script. I would suggest #1 for the easiest setup.