Marriage for me mostly is a legal agreement to tie yourself to another to give you and your partner a definition according to law in regard to taxation and inheritance. Perhaps this is why I disagree to it - as i do not think law should define and dictate my emotional and physical connection to my partner.

Exactly what the oaths says it is - agreement of two parties to care for one another, regardless of circumstances, until death. This includes taking financial responsibility, caring for them physically when ill, but also sharing in joy and love.

The fact that there are legalities around marriage doesn't bother me any more than accepting that the law determines how the government acts about jaywalking or purchasing a passport. I have to admit that I do find the view that marriage isn't worthwhile because it's a legal institution somewhat perplexing; to me, that's like saying I'd never file my tax returns because they're utilizing legalities, even if I know there's money owed and it'd be advantageous to me.

Ultimately, I think that marriage is about people linking together to extend their family. I don't care what the government says about this until and unless they attempt to control it in a manner that infringes upon myself or others in an inappropriate, unfair manner (and is not about protecting the involved individuals - which is why I agree with requiring an age of majority and preventing polygamy). I would add therefore, that I am pro gay marriage, if that's what this is about.

However, I will say on a tangent that after I had children and realized how hard it is to raise kids, and how life changes around them, that I believe a happy marriage is a major advantage to the job (albeit not required), and is probably historically a part of how the whole marriage deal became a legal deal. This said, I think the relationship of children to the relationship is tangential at best. People marry and have no kids, people have kids without marriage, and so on.

The other part of why I think marriage became a thing historically is simply that as humans, we've a desire to declare love and achieve a sense of security and stability in our relationships - which definitely is not about children, and all people deserve the ability to achieve security (again, another reason I am pro gay marriage).

Would have held my peace, but given you specifically said you wanted a wider audience...

Marriage is a religious rite from prehistoric times (same as funerals) that is a formal acknowledgement by society of a change of life state, and a commitment to the resulting family (an important consideration in societies where shortage of resources made citizenship a life or death issue).
That it is religious can be demonstrated by pointing to any culture that has turfed religion - marriage immediately becomes optional, and in a handful of cases was abolished(frex the Bounty Mutineers on Norfolk Island, a community that all Australians should know a lot more about given it's under our jurisdiction).

Marriage isn't a contract; it predates contracts. If it was a contract, then being in love would invalidate marriage, as a contract cannot be valid if one or more contractors is incapable of rational decision making.

Locally, it's also a useful football for stopping churches complaining about governments ignoring the poor - Keating's early efforts to abandon traditional Labor policies were stymied by the churches, but by hammering away at marriage (first through easy divorce/remarriage under the (anti-) family act and now gay marriage) the efforts of the churches has been split, preventing any serious resistance to Labor selling their heartlands up the river.

Well, I'm going to disagree on the 'basically religious' idea. The earliest evidence of marriage that we have goes back to Sumer, where it was an essentially economic transaction (a man provided proof that he could provide a home and that he had means to contribute to an intended family's wellbeing - a commitment that was equally met by the woman's family).

Religion was a factor only insofar as these transactions were recorded by the only literate class - the priestly class. The temples had no power to approve or deny marriage.

All of which is by the by. In terms of marriage today, in Australia, marriage is a bloody Hydra (religious, 'cultural', romantic, secular, etc, etc).

My own definition? Falls somewhere between economic and romantic. It's a public declaration of commitment - the equivalent of shouting from the rooftops, 'Look over here, this is the person I'm going to spend my life loving!' It's also an economic/legal transaction - finances are merged, a home is provided for any desired children, and both partners are protected in case the relationship fails. (Which sounds very cold, but that's the nature of contracts, and my glasses are not that rose-coloured.)

I'm going to leave aside the question of plural/polyamorous/insert term of choice marriage for the moment, simply because I have complicated feelings around that issue and don't think I can speak adequately to it.