It's a lot easier to carry a conversation with them, since they do a lot of the talking and they're easier to get to know. It's difficult for me to become friends with an introverted or socially anxious person, because neither of us do much talking.
I believe that extroverts and introverts complement each other very well. Whenever I'm with a group of friends I find there are usually one or two extroverts who are sort of like the 'leaders' of the group (the ones who drive things forward and do a lot of the talking) and then rest of us who are mostly introverted and make up the bulk of the group. You'll have to excuse me for the terrible analogy here but, to me, extroverts are sort of like glue because they bind the rest of the group together and they're generally the ones who make new friends and introduce them to the group. Terrible analogy over. That's just how I see things from my experience.