Unknown icon on the status bar anyone can figure out what's the 2nd icon from the left ?

Thanks
That icon is one of the apps from Opera Software and its called "Opera Max" thus the "M" icon and it is used for data saving or so it claims. Its shows you your estimated data usage and what you have saved. In their own words "Opera Max - Data Manager is a tool that lets you save considerably on the number of megabytes on your Android device's data plan using a simple procedure that automatically compresses all videos and images that you see (while using 3G) to around half their size. "

Hope your question is answered