Allfeeds "Google Backfill" program compatible with AdSense

Allfeeds "Google Backfill" program against AdSense TOS?

[JoaquinG]

Allfeeds write me about their "Google Backfill" program to replace the PSA ads by Allfeeds ads. By the Alternate Ad URL.

It's against TOS?
They say no, but...

Anyone have a experience?

[vincevincevince]

As the PSAs are only shown when the Google ads are NOT shown then it is no problem re: TOS. In fact, Google provide the alternate ad URL for that reason.

What I cannot comment upon is the case where you have more than one adblock. It is my belief that in that case you cannot use a contextual alternate ad URL, but you could use a fixed or non-contextual one.