I request that you read my comment policy before commenting, especially if you don't know me offline.

If you have a LiveJournal account and want to leave comments on my journal, you can do that without giving Dreamwidth a password or any personal information except an email address. You can follow these instructions (with slight modifications) if you have an account on a site that provides OpenID credentials, too. (For example, any Google or Google+ account should work this way.) Here's how:

1. Go to the main Dreamwidth page
   
2. Follow the "Log In with OpenID" link
   
3. In the "Your OpenID URL" box, put yourusername.livejournal.com. For example, if I wanted to log in with my LiveJournal account, I would type "catamorphism.livejournal.com".
   
4. Click Login.
   
5. Click "Yes, just this time" or "Yes, always" when LiveJournal asks if you want to validate your identity.
   
6. The first time you log in, you'll see a message "Please set and confirm your email address". Click the "set" link and follow the instructions.
   
7. You'll get an email from Dreamwidth containing a link. Follow the link to confirm your email address.
   
8. Follow the instructions. You should now be able to leave comments.
   

Edited to add as of February 26, 2013: There have been intermittent problems with using OpenID to log in to Dreamwidth. The most reliable way to comment is to create a Dreamwidth account, which is free.