Keywords, need plural?

[stanny]

Do you need "s" at the end of your keywords? I heard they get included automatically now or something. Do you include two keywords, singular and plural of the same word?

[Hunnenkoenig]

I don't use plurals, because the search function doesn't looks for whole worlds, but parts of the words. I think...

If you type "second" you will get "secondworldwar" too.
(this is just a stupid example, I had no better idea).