[annalex]

It varies by country -- or, rather, by the Episcopal conference. In the US, the obligation is to do an act of penance, but the faithful are free to choose the nature of the act. The decree is a bit vague, but leaves no doubt that the obligation is still there throughout the year:

Pastoral Statement on Penance and Abstinence

It is all unpacked very effectively in this article:

Are Catholics Supposed to Abstain from Meat Every Friday?.

The article, by the way, convinced me in the wisdom of going away from the blanket insistence on abstinence from meat. In a country like ours, it is no great sacrifice to give up meat, readily available the other 6 days of the week.

[T Minus Four]

So theoretically, one can avoid mortal sin (and the possibility of hell) by driving through McDonald’s and picking up fish sandwiches for dinner, or going out and indulging in sushi.

Why does it have to be so complicated?

[CatQuilt]

In a country like ours, it is no great sacrifice to give up meat, readily available the other 6 days of the week.

That's true but it seems like it's Friday when a good steak is most tempting... Or you go out to dinner with friends to a nice steakhouse or you and some friends decide to get a pizza and everyone else wants pepperoni...

So...you mortify yourself by looking different in front of your friends.

[GonzoII]

"Are Catholics Supposed to Abstain from Meat Every Friday?."

Thanks for that link.