I've just enabled commenter registration and am wondering whether there's a way to have it be one registration that works across all blogs in an installation. Currently, it appears the registration works for the current blog, but the person needs to re-register for each blog on the system, or have it manually enabled.
This is confusing and annoying and clutters the User list as each user is listed multiple times -- once for each blog. At least it would be nice to have a super commenter role or something, or some way to enable commenting for all blogs across a system by default. I see this is an issue that's come up: http://forums.sixapart.com/index.php?showtopic=64864
I wonder if there's something I'm missing, or some work around?
Reported on Movable Type 4.1x

Have you tried commenting on another blog on the system? MT should automatically add the user as a commenter to the 2nd, 3rd, etc blogs when they try to leave a new comment. I'm sure it worked this way when 4.0 was released (and all of this initial conversation took place). I would expect that to apply to 4.1 and 4.2, as well.
The exception to this rule was the Blog Administrator. If you were a Blog Administrator and tried to comment on another blog, the Commenter profile wouldn't get applied. I'm pretty sure I submitted this as a bug way back when all of this conversation initially took place--but that was before the public bug tracker and I can't find the submission now. (Who knows, maybe I flaked and didn't do it.) I don't know how 4.2 might work in this regard--I haven't thought to try it until reading your message just now--and can't test at the moment.
Thanks for the reply. Just created a dummy account to test it out. Here's what I get when I go to the second blog (actually my "link blog" with entries interspersed on my index with the main postings):
"You do not have permission to comment on this blog. (sign out)"
No comment form displays. If I sign out and then sign back in, it creates the necessary permissions and I can comment.
Clunky, and I can already predict the emails I'm going to receive. :) ("Hey, fyi, it's telling me I can't comment!")
Hi, As Solomon wanted, I have some blogs in my site and with one MT 4.21. But every time someone wants to register, he has to register in all blogs one by one. Isn't any way that he can register himself in all blogs with one action?
You probably don't have the other blogs configured correctly. In order to solve this problem, you have to go to each blog's Manage->Users page and do the following:
1) Click on add new user. 2) Select the top entry, which should be "newly created user" or something like that. 3) Click next and select "Commenter." 4) Confirm.
Any new user account should then inherit the Commenter permission from any blog configured like that on your installation. I just tested it, and it worked for me.
As far as I can tell, this is the way it works. User management is controlled on a system level. When you create a new user, it triggers an event which looks up the default user permissions that each blog has, and assigns them to that user. Since most of your blogs don't have Commenter set up for the newly created user, it's not inheriting them.