Once, it was easy.

When pop music first emerged as a major cultural force, it targeted young people. And they were easy to hit.

Take the middle 1950s. In America and England, things appeared to be sewn up tight. Here, the Caucasian middle and lower classes kept their libidos in check, at least most of the time; they did what they were expected to do, whatever that meant, and prepared for middle age by the time they were 20. Across the pond, it was the same, but maybe worse — kids in their teens were dealing with parents so ravaged from the very real effects of World War II that a tiny house, unrewarding job and loveless marriage felt like a blessing they were determined to pass on to their kids.

Into this came rock 'n' roll.

Its rhythmic thrust and raunchy backbeat was implicitly sexual, whenever it wasn't being explicitly so. Within a mere 10 years, the 30-and-under generation would be growing their hair, protesting Vietnam, and rolling around naked in the mud during three-day rock festivals. The zeitgeist had been captured, and everything changed. The music was ingrained in all of it, and most likely, it had been the prime mover.

It's much tougher to feel pop music so deeply these days. That's partly because it's so easy to believe that everything has already been done, that the ship sailed a long time ago, and those of us who weren't lucky enough to have been standing on the shore at the preordained time are simply out of luck.

It's also due to the fact that there is so much pop music, so readily available, in every nook, cranny and crevice of the culture. The idea that the same music used to sell shoes, cars and politicians might somehow be rebellious — life-changing, even — seems increasingly to be nothing more than a pipe dream.

But, against logic, it all seems to be happening again — not in the same way, and not with the same seismic force. But it is indeed happening.

The year just past was an incredible year for music. The big news that emerged from 2009 — and it's good news, too — is that the music doesn't need to enter the mainstream in order to have an effect on the culture.

Meaningful popular music has gone back underground, but who knew that such distinctions as "underground" and "mainstream" would cease to really mean anything? It's all there, everywhere, if you know where to look. And if you don't, some smart-aleck blogger is bound to tell you.

The door is open, and inevitably, some light is shining through. Young musicians who were barely in their teens when Radiohead released "OK Computer" are now fronting bands who aren't afraid to be different — weird, even; hip-hop has been assimilated into almost everything, and is now another color in the palette of every open-minded painter-in-music; major labels have pretty much bitten the dust, and one needn't take out the equivalent of a mortgage in order to record and disseminate their musical wares.

Can I get a "Hell, yeah!"? No? Well, maybe next year. Cuz the way things look from here, it's only gonna get better.

Following is a list of some artists likely to make an impact in the coming year. Some of them already have, though they haven't yet released what one imagines will be their career-defining works. Others are obscure currently, but are poised to break through on some level.

Still others might not make it any further than they already have, but deserve to.

So here are 10 acts to watch in 2010:

1) MGMT

Before you start freaking out and insisting that MGMT broke through in 2008, gimme a minute to explain myself. Yes, the band's "Oracular Spectacular" came out two years ago, and yes, all the hipsters have known about Andrew VanWyngarden and Ben Goldwasser for just about as long, if not longer.

But the band is readying its sophomore major-label effort for early 2010 release, and this is the one that could make MGMT's acid-drenched psychedelic-freak-funk-pop a cultural force to be reckoned with. Or at least give them an audience the size of the one overseen by the Flaming Lips.

2) Blk Jks

This four-piece from Johannesburg, South Africa, plays an unusual but incredibly infectious blend of styles, from reggae to new wave to prog-rock to a skewed pop.

Its "After Robots" was one of 2009's most ambitious releases. If the Talking Heads could break in a big way during the disco era, then Blk Jks have a chance to mean something in the middle of "Generation-Taylor Swift."

3) Animal Collective

Another band known and loved by a sizable underground audience already. But 2010 should be the year that Animal Collective's '80s pop/tribal/jam-band hybrid makes the jump from clubs to concert halls.

4) Bat For Lashes

Natasha Khan, aka Bat for Lashes, is already a hit in her native England, and discerning indie-rockers over here gobbled up her "Two Suns" album in 2009. But every generation needs its own Kate Bush, and Khan is ours. 2010 is her year for the taking.

5) Ida Maria

UK music lovers found Norwegian garage-chaunteuse Ida Maria's "I Like You So Much Better When You're Naked" irresistible, pushing it all the way to No. 13 in 2009. Now, it's your turn, America.

But you'd better get on board the indie-rocker's bus quickly. Ida Maria is already starting to gain a reputation as a volatile performer given to the occasional on-stage meltdown amid suggestions of a problem with the booze. Lord knows we don't need another Amy Winehouse on our hands.

6) Boris

It's fair to refer to Boris as an experimental heavy metal band from Japan. But why stop there? Already, the young trio is starting to assimilate influences that have very little to do with metal, and its live shows have become experiments in genre-busting. That makes them the perfect band for the idiomatic meltdown that will be 2010.

7) Consider the Source

Guitarist Gabriel Marin is showing every indication of being the leading light among the six-stringers of his generation. A year ago, one would not peg a band as ambitious as this tribal-Indian-jazz-jam trio for above-ground success. Now, all bets are off. College kids are buying Mahavishnu Orchestra albums on vinyl. Seriously.

8) Olof Arnalds

A musical prodigy from Iceland who can sing like Bjork and has a sense of musical space not unlike that displayed by Sigur Ros, with whom she is working on her sophomore album, to be released in the spring of 2010. Look out.

9) Dead Leaf Echo

The dreamy, thick and gauzy, late-night-during-a-rainstorm stuff — commonly (and rather unfortunately) referred to as "shoegazer rock," since it's a bit pensive, pouty and overtly grandiose. But these guys are the real deal. Why not a new version of the Cure for 2010?

10) Peanut Brittle Satellite

Buffalo's pre-eminent progressive jam band. Young, immensely talented, smart, ambitious, and a helluva lotta fun, in concert. Should be playing Bonaroo. Someone, pay attention!