Months of hype and media pontification notwithstanding, Monday's debut of "The Jay Leno Show" is unlikely to change the face of television as we know it.

That doesn't mean it won't be fun to watch the fallout. And there will be fallout.

Easily the most anticipated premiere of the new season -- at least among TV industry insiders -- Leno's success or failure promises to reveal much about the short-term future of the National Broadcasting Co.

And, depending on how viewers respond, it could play a significant role in shaping the long-term direction of primetime programming.

As NBC's Leno experiment finally begins, here are five key points to keep in mind: 

Ignore the first month of ratings. They don't matter.

Awareness studies show NBC's marketing team has done a stellar job letting viewers know Jay is moving to 10 o'clock -- and that many of them plan on checking him out.

Add in big name guests such as Tom Cruise and Jerry Seinfeld, and it's a safe bet that ratings for Leno will look impressive for the first week out.

Likewise, it seems logical NBC will take a hit next week, when rival networks start rolling out their new and returning 10 p.m. shows. Unless Leno books Osama bin Laden (or Glenn Beck), he's gonna get dinged as audiences flock to catch up with old favorites.

After the first month of Leno, however, competing shows will have settled into their timeslot. The bright and shiny glow will have worn off Leno's show. And we might even get to see how Jay does opposite entertainment repeats.

There's one exception to this rule: If Leno bombs out of the gate -- if viewers don't even show up to sample his new offering -- then get ready for lots of "Panic at the Peacock" headlines.

NBC's demo love will be tested.

For much of the past decade, NBC has been steadfast in its insistence that demographics are all that matter in TV.

Most recently, we've seen this demophilia in play in the late night race, where Conan O'Brien has helped dramatically bring down the average age of the viewership for "Tonight," beating David Letterman handily in adults 18-49 even as Dave takes the viewer crown.

But "The Jay Leno Show" will test NBC's commitment to the power of demos. There's a real chance Leno could skew older than the typical NBC primetime show.

And while CBS seems likely to continue owning 10 p.m. in viewers, it's possible Leno could slip past some of ABC's younger-skewing 10 p.m. hours.

Will NBC cite total viewer tallies when hyping ratings? Or will it stick to its demo-centric worldview?

There's only one way Leno changes the TV landscape: Total victory.

If "The Jay Leno Show" is a clear-cut bomb, nothing much will really change in TV land. NBC will still be in fourth place, rival networks will pick up a few million extra viewers at 10 p.m., and Peacock executives will begin work on a new way to spin their status as perennial ratings laggard.

If Leno just muddles along, it's another vote for the status quo. NBC saves some money in the short term and competitors continue along as if nothing much happened.

But what if Jay is an unexpected smash? What if, defying all predictions, NBC is able to remain a player in the 10 p.m. ratings game, but with programming costs 1/5th that of other nets?

"If the Leno show works, it will be the most significant thing to happen to broadcast television in the last decade," legendary network exec Fred Silverman told Time magazine earlier this month.

Some would argue nothing will surpass the impact of DVRs this decade, but let's not quibble: If Leno ends up winning a couple nights per week against original competition, it will be monumental.

Rival networks will begin wondering whether they, too, could draw eyeballs with a big franchise player in primetime. Instead of mocking NBC, they might start examining whether to follow its lead-- perhaps starting slowly by launching a variety show stripped five nights a week during the summer.

If there's going to be a rebellion, it'll start with the affiliates.

So far, NBC has done a good job keeping local stations on board with Plan Leno, despite legitimate fears that his lower 10 p.m. numbers could hurt their 11 p.m. newscast ratings. A Boston station's attempt to jump ship was quickly and brutally quashed by 30 Rock.

And yet, if there's going to be any real glitch in NBC's Jay strategy, it will probably be at the local level.

NBC might like to spin how it can turn a nice profit off a 1.5 demo rating at 10 p.m. And it's true that the Peacock hasn't exactly been on fire at 10 p.m. with scripted shows.

But if seeing the former host of "The Tonight Show" 90 minutes earlier starts sending a message to viewers that it's OK to go to sleep earlier, or if comedy audiences end up being less interested in local news than drama lovers, NBC's affiliates could be screwed. Local news profits are already way down due to the bad economy; any further strain on the bottom line could be fatal.

We still wouldn't be surprised if NBC eventually agrees to let a few of its affiliates to try out local news at 10 and Leno at 11 p.m.

Don't be surprised if Leno is cut to three or four nights a year from now.

There were rumors last spring that NBC was mulling the idea of launching Leno as a three-nights-per-week affair. The Peacock flatly denied it, and there's no evidence to suggest such a plan was even discussed.

But a little less Jay might not be such a bad idea, no matter what happens in the ratings.

If the show's numbers disappoint, even by the low threshold NBC has pre-established, there'll be pressure to start building a new roster of 10 p.m. dramas to take over in case NBC cancels Jay in two years.

And yet, if the numbers are solid, NBC would also have cover to cut back Jay. It could start airing scripted shows at 10 p.m. on, say, Monday and Thursday nights without fear of looking like it was bailing on Leno.

Such a move would make sense since it would give NBC the benefit of lower programming costs while also allowing the network a better shot at finding its next big international or syndication hit. And Leno could always revert to five nights during summer repeat season.