Its allowed, i do it, i mailed about it to google and they said its ok, but if they find any violence they might bann all the accounts, as they said...
OK, it's only the third time in this thread: http://adsense.blogspot.com/2008/07/sharing-your-ad-space.html Someone else wants the link?
you can use multiple adsense account on a single site, but not a single page, means each page of the website should see adsense ads form single publisher IDs
Boring, read this and stop spreading lies: http://adsense.blogspot.com/2008/07/sharing-your-ad-space.html
But what will happen, if two posts of different users come in the main page? Whose adds will come at that time?
I have seen this in many websites. If they are a revenue sharing site they usualy allow some adsense blocks for the authors and some are reseverd for the owner of the site.