During the formation of the solar system, the matter which did not fall into the sun condensed to form the planets. This cloud of matter which formed the solar sysetm had a general motion consisting of rotational and linear energy. As the earth condensed from this matter, the angular velocity increased becaue the radius of the cloud decreased to a very small number compared to the initial radius. The wind on the billboards has no effect on the spin, but I think you already knew that.
Wind is the result of solar heating and it simply increases the temperature of the earth.
Tidal stress between the earth and moon is causing the earth's spin rate to slow down. Here's some of the good stuff that's come in recently.