With the exception of the AntiSec movement, most researchers agree that vulnerabilities and exploits should be published eventually so that we can learn from them. But when should we publish them?
Those who practice "Coordinated Disclosure" notify vendors of vulnerabilities privately, giving them time to patch their software and send out an update. They argue that keeping the vulnerability secret from the public makes it less likely that the users running the vulnerable software will be exploited before a patch is released.
Proponents of "Full Disclosure" argue that vulnerabilities (and even exploits) should be published as widely as possible as soon as they are found. One reason is that giving advance notice to any set of people is a risk. People who know about the vulnerability can exploit it while users are still in the dark. When vulnerabilities are disclosed immediately, users can at least make the concious decision to stop using the software until a patch is released. In economic terms, users who don't know about a vulnerability can't user their wallets pressure the vendor into developing a patch, and as a result vendors might leave users vulnerable while they procrastinate the development of a patch.
There are many more arguments and counter-arguments on both sides. It's not always clear which practice is best. It usually depends on the specific case. But in all cases, the right option is the one that reduces the actual count of malicious exploitation. This is something that could be tested empirically for different classes of vulnerability.