Q: Is that also called "swinging"?
A: Most people would say no, it isn't swinging. I, personally, think of polyamory as an umbrella philosophy of sharing and relationship configuration freedom that covers everything from casual swinging to poly-fidelity or group marriage where all parties are exclusive to that relationship. The defining factor for me is that it is done with the knowledge and consent of all parties. Ethical adult relationships with mulitple partners whether the shared activities are of a sexual nature, a romantic nature, platonic or on a spiritual level is a variaton on the theme. Most people who would refer to themselves as a swinger are drawn to the excitement of sex play and while they may well have consistent play partners or develop solid friendships would not be looking for romance. I've noticed that romance with sex partners is rather intimidating a concept amongst couples who are swingers. On the other hand, most people who would refer to themselves as "poly" are looking for deep friendships and romance. That's not to say that romance isn't intimidating and scary stuff for poly couples who are dating other partners but sexual activity is definitely secondary to building a long term loving relationship.
I'm less likely to draw a line in the sand and say oh these are swingers and these are polyamorous people because I've experienced both communities and have seen that there is a blended area in the middle where people are looking for both or looking for just some common ground to build on for starters. Again, as long as the people involved are honest and open with the loves in their lives and themselves - a rose is a rose and it all smells sweet to me.