A question often of newbies.  The green dots on the Mini-Map indicate people.

An Infohub, also known as a Welcome Area, is a place where Residents congregate and socialize.  Click Search > Places tab and search for "infohub" (it's not CaSe-sensitive). This will show most of the Infohubs.

Some areas where there are to be found a lot of people:

    Ahern Welcome Area    http://slurl.com/secondlife/Ahern/4/4/40
    Sweethears Jazz Dance Club    http://slurl.com/secondlife/Sweethearts/197/148/23
    Phat Cat's Jazz Club    http://slurl.com/secondlife/PhatLand/170/104/22

Other ideas for finding people include:

• Search for events ('Search' button at the bottom of the screen followed by the 'Events' tab along the top of the window; search categories include discussion and live music).
• A geographically based group will often announce events.