My own personal opinion of swinging is that it's not for me. I want to touch my partners' souls, not just their genitalia.
And as for the discussion of polyamory vs. swinging:
"Polyamory" and "swinging" are terms with both connotative and denotative meanings, as most terms do. The connotations will vary from person to persons, but the denotations can simply be looked up in a good dictionary.
If you like the the Polyamory Language Page at http://www.polyamorysociety.org
, here are their definitions:
n : is the nonpossessive, honest, responsible and ethical philosophy and practice of loving multiple people simultaneously. Polyamory emphasizes consciously choosing how many partners one wishes to be involved with rather than accepting social norms which dictate loving only one person at a time. Polyamory is an umbrella term which integrates traditional multipartner relationship terms with more evolved egalitarian terms. Polyamory embraces sexual equality and all sexual orientations towards an expanded circle of spousal intimacy and love. Polyamory is from the root words Poly meaning many and Amour meaning love hence "many loves" or Polyamory
vb : Recreational sexual activity, also called "sport sex" where partner's or participant's agree to have casual sex with each other's. There is usually no emotional involvement. A form of monogamy in which usually two primary partners agree to have casual sex with other couples or singles
If these definitions do not suit you, feel free to find others.
Comparing the two definitions, the differences between them seem obvious. In fact, the only significant similarity I find is that they are both nonmonogamous.