A project with issue tracker that you can use to report spam, broken links, or user account problems on Drupal.org website.
"Webmasters" vs. "Content"
Issues related to non-documentation website content, such as case studies, marketplace listings, Planet Drupal feeds, front page posts etc. belong to the Drupal.org content project. There is a separate project for Documentation content.
"Webmasters" vs. "Infrastructure"
If you want to report a problem with the Apache and MySQL installation on drupal.org, the Mailman mailing lists, the Git repositories, and the various Drupal installations on the drupal.org domain, please use the Drupal.org infrastructure project instead.
What about subsites?
Most subsites have own issue queues:
If subsite is not in the list above (e.g. api.drupal.org) - you can use this queue to report problems.
Helping as a webmaster
If you want to help fix issues reported through the Drupal.org webmasters' bug tracker, it is probably a good idea to subscribe to the webmasters mailing list, join #drupalorg channel on IRC and Drupal.org improvements group.
The process for becoming a webmaster is basically participating in issues, providing guidance to people submitting them, and showing yourself to be helpful and knowledgeable about the way drupal.org is maintained. After a while of doing that it will become obvious to the other webmasters that you should have some additional roles to put your ideas into action.
Guidelines for webmasters are in the Drupal.org site maintainers guide.