I think it would make sense to move this FAQ to About LiveJournal from its current section, Site Navigation. Thoughts?
What are LiveJournal's limitations on data?
Usernames and Passwords
Usernames are limited to 15 characters, and the characters that are allowed in usernames are a-z, 0-9, and the underscore character (_). Capitalized letters and hyphens (-) will be converted to lowercase and underscores, respectively. Passwords are limited to 30 characters.
The limitations on the lengths of various input fields are as follows:
- Comments: 9,000 bytes or 4,300 characters
- Comment Subjects: 100 characters
- Custom Friends Group Names: 30 characters
- Entries: 65,535 bytes or characters
- Entry Properties (Currents): 255 bytes or 100 characters
- Entry Subjects: 255 bytes or 100 characters
- Memory Keywords: 40 characters, 5 keywords per memory
- Memory Titles: 80 characters
- Poll Names: 1000 characters
- Poll Questions: 1000 characters, maximum of 255 questions
- Poll Radio and Check Box Options: 500 characters, maximum of 255 options
- Poll Text Entry Responses: 255 characters
- Userpic Keywords: 40 characters, 5 keywords per picture
- Userpic Comments: 120 characters
Edit Personal Information Page
These limitations relate specifically to the Edit Personal Information page.
- Name: 50 characters
- E-mail: 50 characters
- Webpage URL: 255 bytes
- Webpage Name: 255 bytes
- AOL IM: 28 characters
- ICQ #: 12 characters (standard)
- Yahoo! ID: 33 characters (standard)
- MSN Messenger: 60 characters
- Jabber Address: 60 characters
- Google Talk: 60 characters
- Skype: 40 characters
- City: 60 characters
- State/Province/Territory: 50 characters
- About You: 65,535 bytes or characters
- Journal Title and Subtitle: 80 characters each
- Friends Page Title: 80 characters
- Only the 100 most recent entries of your journal will display in the Recent Entries View. You can change how many of those 100 entries display on a single page: however, if you attempt to navigate back further than 100 entries, your journal will begin to use the Day view.
- The Month View (http://www.livejournal.com/users/exampleusername/2005/09/) can only display the first 2,000 entries made during that month. To access subsequent entries, navigate to individual Day Views, like the one linked to below.
- The Day View (http://www.livejournal.com/users/exampleusername/2005/09/05/) can only display the first 200 entries made during that day. To access subsequent entries, use the "Previous" and "Next" arrow buttons found on individual entry pages.
- When filtering your journal by tags, only the 100 most recent entries with that tag can be displayed.
- You can only view up to the 50 most recent entries in a journal when you select the "X most recent entries" option on the Edit Personal Information page.
Other Limits on Entries
- There are limits imposed upon the earliest and latest dates that you can attach to entries on LiveJournal, using the "Entry is Backdated" option. The earliest date posts are allowed to have is 1970-01-01, and the latest date is 2037-12-31.
- The maximum number of comments that can be posted on any given entry is 5,000.
Limits on Other Features
- The maximum number of custom friends groups you can have is 30.
- The number of memories and memory keywords that you can have is unlimited.
- The number of custom mood themes you can create is unlimited.
- The maximum number of custom S2 styles you can have at any one time is 50.
- The maximum number of custom S2 layers you can have at any one time is 150.
- Friends lists
- Link Lists in S2
- Moderated communities
- To-do list items
- Voice posts and transcriptions