It depends on the person's definition of a loser and on what criteria a person judges someone to determine whether or not they are a loser. There isn't a universal definition of a loser. Also people could be a loser one moment, a cool guy the next, then back to being a loser a few hours later. I mean say a programmer is at home writing software in his underwear. He is alone and has been for half a day as he stares at pixels on a screen. He is a loser. But then he goes to a party, gets drunk, has some casual sex and wakes up the next morning with a hangover in his friend's bathroom. Now he's a party animal. Ok that wasn't the best example, but I couldn't think of anything else.
Am I a loner? No. Am I a shut-in? 50-70% of the time. But that's because I'm 14 and can't really go to many places (I don't have the means to get their, don't have the money etc.) So I'm usually at home drawing, on the computer, on the XBox or playing cello. Right now, drawing makes up about 70% of that time.
However, I'm not a loner. I am in several orchestras (most at my school and one of them the SBS Youth Orchestra) and musical ensembles, I do go to friends' houses/ watch movies with friends and I do go to parties (though not super cool alchohol parties- only 2 more years
). I have a lot of friends and I meet a lot of people as well.