adding more than one tag
When choosing a tag. If you want to add more than one hold the ctrl button down as you click with the mouse.
This enables you to choose more than 1 category.
This also works for choosing properties on a Plone page.
Its a very small thing but it took me 18 months of working on Plone sites to figure it out, and I felt a bit stupid when I realised how easy it was.
Working on websites there are so many things like this.
I used to rearrange the contents of a folder manually by pressing the up and down arrows, it used to take ao long. Then about 3 months ago Priyadarshan pointed out using Mozilla you can just drag and drop contents. So much time these little things can save!
If only I had the patience to read my way through a Plone manual from start to finish....
Incomplete help pages at Vasudevaserver.org