Update to the CTP:
Hundreds of thousands of new parallel passages have been added to the parallel passage database by means of an automated study, meaning that over half of all passages in the pre-Qin and Han section of the database now contain at least one parallel with some other text on the site (many of course containing far more). Parallels can be browsed by clicking the yellow parallel passage icon to the left of a paragraph, and can be searched using the Advanced search function.
In addition, the parallel passage display now provides a visual summary of text reuse within the selected paragraph. Parallel groups are indicated using shades of red; the stronger the shade of red a region is shaded, the more parallel groups it belongs to. Clicking on a shaded region jumps down to the corresponding list of parallels below. More details available here: ctext.org/tools/parallel-passages .