Service mark symbol. The service mark symbol (â ), the letters SM in superscript style) is a symbol used in the United States to provide notice that the preceding mark is a service mark.
Size matters: The micro and mini USB connectors are of similar width. But the micro connector is much thinner (smaller vertical dimension). Some product designs were not able to accommodate the height of the mini receptacle and the new thinner receptacle will encourage and allow thinner products.
Key difference: Mini USB predates the micro USB and both have five pins. However, mini USB has a life cycle of 5,000 connects and disconnects, while, micro USB has a life cycle of at least 10,000 connects and disconnects. Also, micro USB is smaller than mini USB.