使用分层URL与平面的优缺点？

I'm building a large news site and we'll have several thousand articles. So far we have over 20,000. We plan on having a main menu which contains links which will display articles based on those criteria. Therefore, clicking "baking" will show all articles related to "baking", and "baking/cakes" will show everything related to cakes.I'm building a large news site and we'll have s