To me its like showing respect to YPN and welcoming the competition.

But YPN is still not allowing to put other contextual ads where there are YPN ads so imo it will take some weeks (or months) to get benefit of Adsense's relaxation.

Jennifer Slegg blogged about it and gave some detail information about it

what other ads are acceptable to google now, they used to freak about it, i would like to load my site with ads who needs a menu when you could have text links instead

is jensense.com official partner of the google adsense ?

Yes this true, I sent a mail to google about it, this was the reply:

AdSense publishers may display ads from other contextual ad networks on
the same page as Google ads only if the formatting or color scheme of
these ads is sufficiently different from the layout of the Google ads. In
other words, if you choose to place non-Google ads on the same site or
page as Google ads, it should always be clear to the user that the ads are
served by different advertising networks and that the non-Google ads have
no association with Google. If the formats are naturally similar, we'd ask
that you use different color schemes for the competing ads.

Of course, we're constantly investing in our advertising technology, and
we believe that Google ads will monetize best for most publishers. Be
aware that the addition of third party ads to your site may cause fewer
users to click the Google ads on your site and thus your AdSense earnings
may decrease. We'd also recommend that publishers be careful not to place
excessive advertising on their sites, as doing so may result in fewer
repeat visitors.

I run kontera with Adsense on same page

I have just signed up with kontera are they any good

I never got an email from Google saying it, but did notice that you can use adbrite with them now. I think it was adbrite or another contextual ads program. It said on their site. It was not googles site though so they could have been wrong, I don't know.