// Current hash format: starts with a '#'
(#hash) here's text
(#hash) @<nick url> here's text

// New location format: valid URL-like + '#' + TIMESTAMP (verbatim format of feed source)
(url#timestamp) here's text
(url#timestamp) @<nick url> here's text

// New format for custom references: starts with a '!' maybe?
(!custom) here's text
(!custom) @<nick url> here's text

// A possible "Topic" parse as a thread root:
[!custom] start here
[custom] simpler format

s
function setPostIndex(post) {
    // Current hash approach
    const hash = createHash(post.url, post.timestamp, post.content);

    // New location approach
    const location = post.url + '#' + post.timestamp;

    // Unchanged (probably)
    const subject = post.subject;

    // Index them all
    addToIndex(hash, post);
    addToIndex(location, post);
    addToIndex(subject, post);
}

// Both should work if the index contains both versions
getThreadBySubject('#abcdef') => [post1, post2, post3]; // Hash
getThreadBySubject('https://example.com#2025-01-01T12:00:00') => [post1, post2, post3]; // Location