I'm currently monitoring a website auction where the owner has placed two Adsense units next to each other at the very top. To make matters worse, he also added a link unit above, and another large 728x90 banner below.
Another thing that I noticed was that the left Adsense unit appears to be an image ad unit.
I cannot find the reference, but I'm pretty sure I read somewhere that placing Adsense ads next to each other is against the TOS.
I remember reading here a reference to that and there was a link to Google where it appeared "if you do this then this is what the users sees on an average monitor" (something like that).
and it pictured two units together before the title of the page, ant it was mentioned as not ok. But anyway I've seen lots of sites like that (all of them spammy). No, it didn't say on the page "don't do it or, this is against the TOS" but it was clearly a consideration to take in count.
Not against but can be ? We have had tons of sites with two ad units right next to one-another. Some survived the Panda and some didnt. I would say try it and if you are happy with the earnings just keep it.
Definitely not against the TOS, for years I have had several "parked" single-page informational domains like this. If done correctly they look really good...hmmm...time to sell those domain names I reckon!