UML has a jungle of Diagrams.
Profile Diagrams, Class Diagrams, Package Diagrams...

However, (IMH-and-not-too-experienced-O) I quite see that doing each and every diagram is overkill.

Therefore, which UML Diagrams are more suitable in a web context, more expecificly a blog (we want to build it from scratchs).

_{I understand that just because I used UML Diagrams does not imply that our code would be great and brilliant... but, it certainly would be better than just unplanified code...}