'Upgrade to'

In various parts of the site, you can see links that invite you to upgrade to a Plus or a Paid account. As House Ads and CProd modules, these links are internal advertising. They generally link to /manage/payments/ or /shop.

DidYouKnow pages
They are pages which promote a specific feature of LiveJournal:

Create a Poll

Mobile Posting

Advanced Search

Domain Mapping

Buy more stuff links
On the Edit Userpics page, paid users can see two 'Get more userpics' links to /the Gift Shop when they've reached their limits.