User notes are an important part while reading the PHP Manual. Some user notes contain very valuable information. We basically set up the user note system, to let people add their own examples, warnings about functions, language elements, etc.
Note, that the user notes are not moderated before they appear on the PHP sites, so the quality of content cannot be guaranteed.
If you can't find a solution for your problem in the user notes, you may consider reading the section How to find more information about PHP.