This may be in the wrong forum.
We have a site that's set up basically like this:
Home
- Blog subdomain, account required to manage subscription
- Forum subdomain, account required to post
- Store subdomain, account required to buy
- Auto listings subdomain, account required to list for sale
- Property listings subdomain, account required to list for sale
You also need to provide an email address to subscribe to the site newsletter, and to send forms throughout the site, but those are not a concern.
How can we allow the user to sign in once for all the subdomains listed above? I saw someone in a forum somewhere say that it's not worth the trouble to do this, but we feel that all these user sign-ins clutter the experience. I've seen various SSO systems but I'm not sure if they're what we need.