You can publish your own decks, which will allow others to find them when they search for a deck. In fact, use the Search to search through all published decks.
You can also challenge other users to a duel once a deck is published - you and the other user will then both have access to the same deck.
How to publish a deck
If you click on any of your decks to view the deck details page, you will see a side-bar menu (three vertical dots). Choose that, and then Publish Deck.
Here, you can publish your deck, publish updates, unpublish the deck, and view the number of subscribers to the deck.
The first time you publish, you'll be asked to provide your name. You can also set this name in the Settings.
What is published
When you publish a deck, the dates, cards, links (see below for a clarification) & categories of the deck are published, along with the deck's title and description.
Your own performance, revisions, and other metrics, are not published—those remain private.
When you create links, they will generally be between dates in the same deck. However, you can create cross-deck links too, between dates in two different decks. When you publish a deck, TimeToTime only publishes the links that are between dates within the deck being published - it does not publish dates that reach across decks.
You may also choose not to publish links at all. In this case, any link that does not have the "Should publish if deck published" flag set, will not be published. By default, this is not set - so by default new links you create will not be published.
How to publish changes
When you publish a deck, TimeToTime effectively makes a copy of that deck. If you add dates to the deck, or make changes to any cards or categories, then those won't be reflected until you publish those updates.
When you do publish changes, TimeToTime displays a summary of the changes that will be published.