Mailing lists
User mailing list
Don't look here for advice on which mailing list software to use. You may want to use some ready made lists like on SourceForge. You can also decide to just point users to the general plone-users mailing list. That's fine. See plone.org/support.
But if someone has a problem with your product and mails the plone-users list with a subject line of just Problem you are likely to ignore that message. If he instead uses a mailing list specifically aimed at your product, you are much more likely to read his mail. Well, that's one reason to create a mailing list for users.
If your product is very successful and also draws
attention from a lot of developers who want to embrace and extend your
code, you could add a mailing list specifically for discussing
development. But stick to one user list for now.
Issue mailing list
There is one other list that you may want to add: a list where bug reports are automatically sent. For example if you added a Poi issue tracker to your product page in an earlier step, you can choose to send any bug reports to a few email addresses or you could let them be sent to a mailing list. Anyone interested can subscribe to that list. This safe you some hassle.
Newsgroup via Gmane
When setting up the user list for my own eXtremeManagement product, some fellow developers told me they would like the list to be available as a newsgroup via gmane.org. That is fairly easy to setup, so I suggest you do that as well. Just follow their instructions. I'll add one remark: to make sure users can easily find the newsgroup, make sure you stick to the naming convention for plone lists. In this case I would suggest as a group name: gmane.comp.web.zope.plone.shinynewproduct.
After some time (could be several days) you normally get an email with a courtesy copy of an article that has been posted to the gmane.discuss.subscribe newsgroup as well. Follow any instructions that you read there, if any. Usually this will tell you that everything is ready and the newsgroup will automatically be created after the next email is sent to the mailing list.
Make sure you mention your new
mailing lists and newsgroups on your products page in the Plone
Software Center on plone.org. Okay, now you can start using the lists.
How about announcing the first release of your product there? Read on.
