Articles threads are invisible, linked boxes (beads) used to aid the reader in following the flow of a story through a PDF.

When a viewing application such as Adobe Reader detects an article thread, it is able to present the text boxes in turn for easier reading of the complete article.

Some applications can use articles to reflow the PDF or convert and export stories into other formats such as HTML.

There is no limit on the number of article threads a document can have.