For digital publishing (PDFs and SWF), CS4 vastly improved cross-references. You could set up dynamic text that updated automatically if page numbers or paragraph numbers changed. This made long-document production—like textbooks, catalogs, and annual reports—far less error-prone.

Designers no longer needed to squint to align objects. Smart Guides appeared dynamically as you dragged objects, snapping them to the baseline grid, margins, or other objects' edges. It sounds simple, but this dramatically reduced the time spent on alignment.

For technical writers, instructional designers, and textbook publishers, Conditional Text was a game-changer. This feature allowed users to create multiple versions of a document within a single InDesign file. By applying conditions to text, a designer could show or hide specific content based on output requirements.

Can't export PDF/X-1a for print. Solution: While CS4 supports PDF export, it lacks modern PDF 2.0 standards. Stick to PDF/X-1a:2001 or PDF/X-4. Always "Flatten" transparency before sending to a print vendor who uses modern RIPs.