Another very common error is not getting the e-mail at all. While there is already an FAQ for "Where are my notification emails?" that covers errors with not receiving e-mail from LiveJournal it is not very intuitive for people experiencing problems with receiving their validation e-mail. Nor is the "How do I get validated? It says I'm currently not validated!" FAQ which also contains a brief description of spam filter issues.
The "Why are there errors when I try to validate?" FAQ needs to be appended to include a link to the "How do I get validated? It says I'm currently not validated!" FAQ which describes problems encountered by mail filters as well as how to correct an incorrectly typed e-mail address. Both issues that may be considered "errors" in the users mind and therefore including them in the "Why are there errors when I try to validate?" FAQ would make finding the information they need more intuitive.
The FAQ might be appended as follows:
"If you are experiencing problems with receiving your validation e-mail, please see: http://www.livejournal.com/support/faqbrowse.bml?faqid=11"