Sticky posts: There's now an option on the Update page to "Make sticky post". Selecting this option will cause the entry to show up as the top entry to anyone who views your journal. This works for both personal journals and communities. You can only have 1 sticky entry in each journal; if you attempt to post a new entry with this option enabled, it will become the new top entry in your journal and the previous sticky entry will revert to being a normal journal entry. Your sticky post will have this image in the same section as your the security icon:
Delayed entries: Changing the date & time of your entry to a time in the future will now cause the entry to be posted at the date & time you have entered rather than immediately posting it. You can view & manage the delayed entries you have scheduled to post at http://www.livejournal.com/manage/scheduled_posts.bml.
lj-spoiler tags: You can now add spoilers to an entry through use of the [Spoiler (click to open)] tag. This is similar to an in that it will hide all content inside of it, but it does not require a new page to load when clicked, and it works in both entries amd comments. You can customize the text by using the format [Custom text goes here]. There is also this new button in the Rich Text Editor: which will cause all highlighted text to be placed inside an lj-spoiler tag.
Latest entry: You can now view the latest entry in any user's journal by adding /latest to the end of the URL for their journal. Example: http://exampleusername.livejournal.com/latest will take you to the latest entry posted by exampleusername.
Bug fixes:
Comments left by deleted accounts will display again, instead of incorrectly showing all comments as having been deleted.
Comment headers should no longer incorrectly be excessively large for comments with subject lines.
Bold, italic, and underline buttons in the comment form will now insert HTML in the correct places when used.
Userpics should display properly on your latest entries page & friends page when the option to use the old style comment pages is enabled in Minimalism.
Flexible Squares styles have had their comment page navigation/pagination options restored.
Email notifications now contain the correct URL for the options to screen or delete comments.
Other changes
The way Tokens are purchased in the LJ Shop has changed. There is now a slider to select how many Tokens you wish to purchase, or a text field to manually enter the amount (up to a maximum of 65,000). The cost of tokens is now a flat $1 per 100 tokens regardless of how many are purchased.
[edit] Known Issues
Content inside [Spoiler (click to open)] displays strangely when expanded in some cases (when other text exists on the same line where the tag starts, and paragraphs/line breaks are causing issues)