>>23617832
the posts are 'pink' in the default CSS styles of this page when you post them, or if you highlight that posters posts by clicking on the post ID number.
there is no significance other than someone took the screen cap when they had either highlighted the post or just posted it themself. As it has a (yew) (i spell it so it won't get picked up in searches) probably the screen cap was made just after it was posted.
If you would like other colors you can change the styels in the Options menus, or design your own styles too. The options menu is accessed from the bracketed 'Options' at the top right of the broweser page as configured.
Choose from there 'theme' and you find a place to customize the CSS if you know how to do such things. As well, at the bottom of that pop up a pulldown list allows one to choose different stock themes which significantly change the user experience.