In our South Bay Poly information, we state that "poly" is not the same as "swinging". I've recently been involved in an e-list discussion of whether swingers should be included under the poly "umbrella" -- i.e. is swinging a type of poly?
I personally don't think so. I think our goals and attitudes are different. I would say, though, that we are both part of a larger critique of monogamy. We both are dissatisfied with traditional monogamy. But we propose different alternatives.
Swinging involves a couple allowing each other to have sex with other people, preferably another couple. The sex is limited to its physical aspect. Emotional or romantic involvement with the outside partners is discouraged.
Polyamory, as I understand it, discourages nothing. Emotional and romantic involvement is seen as natural. There is no attempt to restrict extra-marital involvement to sex. Polyamory encourages the development of relationships beyond sexuality, including long-term commited relationships.
For these reasons, I see swinging and poly as significantly different.
Part of this involves my personal tastes. I'm much more interested in love than in sex. I've been in love with people I haven't been sexual with. I feel much happier about them than about the people I've become sexual with, with no sense of connection. I don't think that makes me "sex-negative". I enjoy sexuality, but not "by itself".
I'm not interested in keeping swingers away; I just want them to understand that the poly focus is different from theirs. I think some people can be both polys and swingers, just like people can do both poly and BDSM -- but they aren't the same thing.
I don't think that people who are looking only for sex should consider themselves polys. Sometime polys may go "looking for sex" -- but generally they are looking for more than that. So it's best to keep the two groups distinct in our minds, even for those who are interested in both of them.