Pillows advertised as “snore pillows” tilt the head backwards and can improve snoring in some people, but there is no reason to buy these if you can use your own pillows properly. The bottom line: using large or too many pillows may be soft for your head but bad for snoring and breathing patterns.
I wondered if they were just another marketing ploy. They do seem to look a bit different from ordinary pillows though with a central deep indentation. I my friend can't achieve that with my her current pillow.
We have just bought new pillows after advice from a friend. It has certainly stopped DH from snoring so far, and has cured my neck pain too. They are Emma pillows, not cheap! But we are definitely converts and getting a better sleep now all round. They are not advertised as anti snoring ( as far as I know) but designed to support the upper spine properly.