For an overview of the membership plan see IMSLP:Membership Q&A.
For more information on the reasons behind this change, see this announcement on the IMSLP Forums.
Please note that some newly-uploaded scores may only be available after a day or two to non-subscribers.
I am a new contributer and an avid "all-music-should-be-public-domain" advocate.
I live in Tzfat, Israel, and I am a professional musician.