»1. Features

A LiveJournal installation comes with many configurable features available “out of the box”, including but not limited to:

Journal related

Journaling service
LiveJournal's core function. Users are able to submit journal entries and "publish" them on their account's journal page.
Community journals
Journals that many users can post top-level entries to. This allows for more long-term and public discussion than comments in a user's journal.
Friends list aggregation
Users are able to add other users to their ‘friends list’, which permits them to view all journal entries from their friends in an aggregate form.
Friends filters
Users can view a subset of their friends lists at any given time.
Calendar view
Users can see a record of all of their posts in the past, and choose to view those posts by a specific day (allowing easy access to old posts).
Message boards
Users can enable or disable message boards for individual entries or journals as a whole. Users can choose to allow anyone, registered users only, or friends only to post. Users can choose to ‘screen’ comments — make them visible only to the owner of the journal — and choose to set certain levels of comments to be automatically screened until approved (such as a user who may choose to screen all comments by non-friends until they are approved).
Email notification of comments
Users can choose to receive an email notification when someone comments on one of their posts (in the user's personal journal or in a community journal) or replies to one of their comments (in the user's personal journal, a friend's journal, or a community journal).
Security levels
Users can specify who can read their journal entries. Entries can be public (all can read), private (only the user can read), protected (only the user's named "friends" can read), or custom. Custom security allows a user to specify up to 30 subgroups of their friends who can read the entries.
RSS feeds
Your installation publishes all public journal content as a RSS feed for syndication on other sites. LiveJournal allows users to syndicate external RSS feeds onto LiveJournal, to read on users' Friends page. (Adding RSS feeds to user's friends list needs "syndication points", and each feed costs a certain number of points based on how many users are watching the feed).
Moods, mood icons
Each entry can be given a ‘mood’, to describe what the user is feeling at that time. Users can choose to add a ‘mood icon’, which is a small picture to depict that mood. Users can create their own ‘mood icon’ themes for use in their journal.
Users can create different types of polls, to get opinions, information, or thoughts from readers.
User picture icons
The ability to upload small "avatars" that represent the user throughout the site.
Personalized subdomain
If configured, users can view their journals at http://username.domain.com, as well as http://www.domain.com/users/username and http://www.domain.com/~username.
Customizing the display of the journal page
Users can create journal "styles" from scratch and have precise control over appearance of their journals.
Friends of Friends feature
Users are able to see a list of entries by the users who are named as a friend by their friends, but not by the user.
Downloaded clients
Users can download a program to make journal entries (and perform some other actions on the site) from their computer, rather than from the website.
Tell a Friend
With one click on the ‘read entry’ page, users can send an email to someone else about an entry, calling the recipient's attention to it.
Export feature
Users can download their journal month-by-month, in XML or CSV format.
meme tracking
Users can view a list of URLs that have been most referenced in journal entries site-wide. Users can also check to see where those URLs are being referenced. (By some slight alteration, users can also see if anyone on your installation is linking to a specific URL, and where.)
Random feature
Users can view a random journal from a subset of users who have updated in the past 24 hours.

Account related

User bio
Users can provide information about themselves, which is displayed on a page that can be viewed by visitors to their journal (the ‘user bio’). Users can specify contact and location information (email, AIM username, Yahoo! ID, ICQ #, MSN Messenger username, Jabber address, city, state, country, etc) and specify the security level of that information (public, private, protected)
Site search
Users can search by contact information — finding other users by email address, AIM username, Yahoo ID, ICQ #, MSN Messenger username, Jabber address, etc — to locate people on your installation.
Users can list up to 150 one to four-word interests in their user bio, which other users can search for.
Similar interest search
Users can see a list of those users whose interests match most closely to their own, based on an index that weights both number of interests in common and rarity of interests in common.
Popular with friends search
The ability to see a list of the users who are named most often as a friend by the user's friends, but not by the user.
Domain forwarding
Users can forward their domain to their LiveJournal (so that, for example, http://journal.example.com would forward to the user's LiveJournal at http://www.domain.com/users/username)
Journal embedding
Users can ‘embed’ their journal into their home pages, displaying their journal as part of an external home page. (This is different from domain forwarding; with domain forwarding, the content is served from the LiveJournal installation; with embedding, the content is first pulled onto the user's server and then re-presented.)
Text messaging
Users can specify their text message information and display an option on their user bio page to allow others to text message them. (This allows users to receive text messages without having to make their information public.)
Memory list
Users can name any post on the service as a ‘memory’ — a LiveJournal version of bookmarking. Memories can be categorized with different keywords, so that users can more easily sort their memories.
To-do list
Users can create their own ‘to-do’ list — reminders or important things to do — and track percentage complete and progress on each item.
Birthday list

Site related

Users have access to the directory of users, where they can search by location, age, interest, etc.
Users can use a more complex update page, which includes "boxes" of several other features, such as statistics and birthdays, on the same page as the update page.