Hey, 

ÖBB is sending to Newsletter readers that have a ÖBB Account an email with a coupon with 4 reservations for free for trains with optional reservation of ÖBB. The coupon is automatically linked with your ÖBB account. 

I tried now to book also DB trains, and it works (I tried till to the “paying” site). I don’t know if everybody with ÖBB account gets this or only people which have also the newsletter. 

This free reservation works only for trains with optional reservation system, and in the text it says only ÖBB trains. 

You have to book a reservation till 11th of September to use this free reservations. 

I just booked three reservations via oebb web site where I have an account. I was not signed up for the newsletter but all three reservations were free and I was only charged for the supplement on one of the reservations. We are travelling as a family of three so the savings were a nice surprise!