Develop/Single sign on
The OpenStreetMap project would ideally support single sign on across the editing interface, the wiki, and the other systems. Several different types of Accounts are in use. Unification of the logins/accounts would, of course, be a good idea. It has been discussed before, but it's a bit of development effort which hasn't happened yet. There are also complications around policies for changing user name.
A basic discussion of what is involved in any single sign-on scheme, technically, is here: https://lists.openstreetmap.org/pipermail/dev/2008-November/012859.html
People involved
It would be nice to have a list of persons who are actively working on this issue and what they are doing.
Services
For a list of services look at the Account page.
Proposals
OpenID Connect
https://github.com/openstreetmap/operations/issues/507