Does capitalization matter for tagging?

Tags are not case sensitive, however, if the first person to create the tag uses lowercase, all uses of the tag will have it in all lowercase.

So if some tag it trust and some tag it Trust, all will be pulled into the trust tag?

Thanks!

Correct

Tags can be renamed as well.  If you go to the application that has the tag, you can click on the pencil icon > Manage Forum (or blog, etc...) > Tags:

This will allow you to rename the tag, but it will rename it across the entire site.