What yin and yang really mean

Help I can't read your story!!!!

Your english is just fine. Thanks for helping me understand

As a Chinese, I think I can provide some clues.

"Yin(陰) and Yang(陽)" is the foundation concept of Taoism(No matter the religious one or ideology one). It states that everythings except "Tao"(道)(Another difficult concept, but you can assume it is the origin of everything) belong to either "yin"(black) or "yang"(white). For e.g.: men are yang and women are yin.
Yin and Yang complements each other, as shown in the logo. So it is assumed that everythings have their "opposite". For e.g.: hot to cold, long to short, peace to chaos

When a thing goes too far and reachs the extreme, it will go to another direction.(物極必反) So the taoists stress "the spirit of mediocre"(中庸之道), in order to have a peaceful life, spend less efforts in solving problems and lengthen the lifespan.

That's what I have learnt from my lessons and social life. Forgive my poor English.

i think it means good and bad or something? i could be wrong. but the black is the bad (and the white dot in the black part represents that all bad things have a little good in them) and white is good (black dot reps that good always has a little bad in it). anyway, thats what i was told. hope it helps answer your question. =3