Yes, It’s true. Today on most of the blogs the google ads stopped showing and some public service ads started appearing. The news became more truthful when some blogger reported about this on Webmaster Forums like DigitalPoint. This problem can also be seen on my blog. See this screenshot:
Google explains properly why PSA’s appears on a blog. See here.
I hope Google solves this problem asap because many bloggers are getting irritated by this situation.
*Update:
The Issue has been resolved 
See here in the adsense forum.
Since it’s morning in US therefore Google officials are sleeping right now..So they can’t reply to this issue..Therefore we will have to wait few more hours.
Yes this is only true for blogs hosted on blogger. Hope google solves the problem soon.
Thanks… Was worried I did some mistake or was banned!! Hope this gets solved soon.
@Dr.Vishaal Bhat
Yup..hope it get’s solve asap..Blogger blogs loosing their income through adsense..sad
haha I thought my account was banned too!
Yeah I can just imagine how many people thought there Adsense account got banned. Last night before I went to bed I noticed the issue. I do hope that Google gets this fixed soon as well as everyone so that our Adsense Ads will be showing again.
I did notice that the link unit is different which may have caused the problem. They may be trying something new which caused a glitch in their system. Hope it returns back to normal soon. People must have got a real shock when they went to look at their Adsense earnings this morning.
Sincerely,
Jamie Boyle
http://www.MakingMoneyForLife.com
Was it the first time this has happened to Google? I was worried for a moment there.