Let’s say you have previously accepted content from community members requiring only an email address. This could be forum posts, photos, reviews, comments, whatever.

Now, you’ve decided it’s time to go deeper and create an account system so that you can offer additional features and connect more directly with the community. And you want to convert those old members (and their content) into this new system.

How should you do this?

You could automatically create the accounts and then email people, allowing them to confirm their address and create a password. No matter how you word it, this is tricky because in most circumstances, people don’t like having an account created for them without having been asked first, even though it might make total sense from a technical/software evolution standpoint.

If you go that route, the most important thing is to word it in a way that says they can create an account if they’d like to. You should avoid anything that sounds like “we created an account for you, here’s how to use it.” Give them a choice, not a command.

A different, more palatable approach might be to simply let people create accounts themselves the next time they try to submit content. Install an automated check in your registration process to see if they have posted any content previously using the same email address. If they have, ask them to claim that content, and then associate it with their account.

This isn’t really a huge technical leap if you have any developer resources at all, and it’s a good, solid, community-first approach to accomplishing your goals.