Can I use a contextual alternative to PSAs in Adsense?

[Momo]

I have 2 units on my pages, and a lot of times, the other unit is not displayed, and I was wondering if it is possible to use another contextual program as alternative? What if only one is filled and the other is not, and displays the other program's contextual ads? That would be violation of Adsense TOS.

Is there any way to ensure that they won't be displayed at the same time? Or should I just use noncontextual alternatives?

[ServerUnion]

This is not allowed. You can only have one program running per page. You can however set an altername ad, or even match the color to the background so the PSA will not show. Good luck

[Momo]

I'm currently using the code that will reduce the space if there are no ads.

Could you suggest possible programs that I can use as alternatives?

[Dekker]

chitika, adbrite

azoogle

[Momo]

In Adbrite, I can only use the 'Your Ad Here' mode, and not the one with network ads, right?

[Dekker]

ask. but i dont believe adbrite is contextual