This blog post by Brett Terpstra provides an update on his Markdown Quick Look previewer, Marked QL. He discusses a price increase from $4.99 to $9.99 in anticipation of new features, shares challenges faced with support due to custom UTIs created by other apps, and outlines plans for future updates, including new features and bug fixes. Terpstra also encourages readers to help promote Marked QL on social media for a chance to win a free copy.