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.
All Micro USB cables are the same. Its like the old 'HDMI cable' debate. Its digital data, unless there's a break or something, a better quality cable isn't going to make any difference at all! As for the chargers..