I think most people should know this already although I'm not quite sure about that so posting anyways.
Most often than not I receive emails being sent to mailing lists where the the individual recipients don't really know each other or even if they do they might not necessarily want the other recipients of their existing email address. I personally don't really mind disclosing my information (as having my blog and numerous online profiles would easily help you figure out my email) but there is a very high possibility that others would actually mind doing such and unless you are absolutely sure that they don't then use BCC (blind carbon copy) for those email recipients instead. [more]
Don't get me wrong, this is a free world and do as you please but your recipients will likely appreciate proper use of the BCC field and not to mention that it would minimize spam. In it's own little way make the web and the world a safer place. we need not worry about black hat hackers employing complicated techniques to look into email address databases or gain access to a server if they'd need only to compromise a few email account and if those accounts happen to be full of valid mailing lists emails, then they're out for a treat. We don't really want that do we 🙂
refers to the practice of sending a message to multiple recipients in
such a way that what they receive does not contain the complete list of
recipients…
BCC on Wikipedia