Why did Yahoo do it?

It's probably due to marketing. Yahoo is a brand and, like all businesses, it aims to generate more and more audience members. So, they probably believe if they change their formats/look/label/brand, it will target different groups, gaining more members in the end. As for changing it back, probably not possible. Sorry

i dont think there is any way you can revert back to old layout..IMHO, i like it.."to each his or her own i guess" once something like this is implemented by the answers staff..it is permanent. new styles, new features are slowly being intergrated to improve this service as a whole

I have always known this site, it has never been any different since I have been using it since April 2006

I dont notice a change. How long ago did it change?

right