From version v1.6 you can view information about vertices, faces, normals and creation order. These options can be used to debug a mesh
and are very useful to debug python scripts.
The information is displayed in EDIT mode and OBJECT mode and can be mixed with any measure option.
I know that Blender can show the vertex number in debug mode, but it’s more handy to have a button for that.
Download: https://github.com/Antonioya/blender/tree/master/measureit
Examples:
Very very good Antonioya,
A really essential tool! Congrat and of’course a big Thanks!
Bye bye
Spirou4D
really nice addition 
You do a great job making Blender better for user and programmers!
Great tool you have developed
Thank you very much for making it better & better.
Thanks for the creation and improvement of measureIt. This is really a useful tool.
Brilliant again! Thank you for sharing! One little humble idea: support a box behind the index, since sometimes it could be hard to see due to user’s customized theme, though the text color can be changed.
(And just wonder where the “edge” debug is… :))
EDIT: And how about this to avoid scrolling up and down too often?
since it can display the index number of vertex and face? Why let edge be alone?
