Before we get too far into 2016, it's worth taking one more look at what happened to media in the year that just ended. To paraphrase the old saying, ignorance of history dooms you to repeat it. And some of what happened in media in 2015, we really want to avoid repeating.

For example, it may seem ironic to criticize the media for giving Donald Trump so much attention by writing a column that gives him even more attention. But no list of the Most Impactful Media Moments of 2015 would be complete without a close look at how the reality TV star-turned-GOP front-runner affected news coverage.

Outside of politics, the pace of change seemed to accelerate in all corners of media in 2015, as technology spurred creation of new platforms while slicing up the audience even further. And everyone struggled to keep pace with an audience increasingly insistent on instant access to the best content available anytime, anywhere.

Here's my list of what transformed media and media junkies over the past 12 months:

1: Trump. The numbers are astonishing. Donald Trump received more than a quarter of all time devoted to campaign coverage on the Big Three TV networks' evening newscasts between January and November 2015, according to analyst Andrew Tyndall (Trump didn't even declare his candidacy for the GOP nomination until June, but Tyndall says there was little coverage of the presidential race on networks' evening newscasts before that month). And because Trump is a viewer magnet, media outlets' responses to him have exposed just how much ratings, audience and revenue can drive news coverage. As Trump debuted his first TV ad this week, news programs gave him loads of free exposure by airing it in their own shows. Candidate debates have been transformed from programs presented as a public service to showdowns hyped like boxing matches. Trump has dictated the terms of his coverage on many media outlets, calling interviewers likely to treat him as a pal and briefly ejecting Univision anchor Jorge Ramos from a news conference. Entertainment outlets like Saturday Night Live featured him in ways no other front-runner for a presidential nomination has been featured. It wasn't until Trump advocated halting immigration by Muslims that increasing numbers of media outlets realized how badly this imbalance of coverage has underserved the public. Now, outlets and reporters disparate as the website BuzzFeed and NBC icon Tom Brokaw have criticized Trump more directly, even as their reports added to the coverage imbalance. All this, before even considering the ways such actions help mainstream Trump's stereotyping, prejudice and misinformation. My hope for 2016 is that news outlets break their addiction to covering every outrageous thing Trump says and spend a little more time telling us about the other people running for president. (Yes, NPR has covered Trump too. But as our ombudsman has noted, we haven't let him speak unfiltered and without context the way too many TV outlets have.)

2: Streaming rewrites the rules of TV. Not long ago, it was accepted wisdom that cable systems would never allow viewers to buy access to channels a la carte, or piecemeal. Then 2015 gave us Sling TV, HBO Now, Playstation VUE and Showtime's streaming service — all new ways to get cable channels online without paying for cable service. These platforms, intended to grab millennials who will never buy cable, served notice: We are increasingly in a media environment where the consumer's will triumphs over all. Even companies that make most of their revenue from traditional cable TV services are offering streaming services that may eat away at their core business model. And New York Times TV critic James Poniewozik rightly notes that original shows aired on streaming platforms like Netflix and Amazon are becoming a separate genre, changing how we all view TV. Next comes the big question: What happens to local TV stations once broadcast networks like NBC and CBS build out their streaming services, bypassing the local guys to connect directly with viewers?

3: #BlackLivesMatter, #AllLivesMatter, #WhitesAgainstTrump and Black Twitter: The debate over privilege and prejudice goes viral. Protests over white privilege and policing really kicked in hard during 2014. But the discussion moved to new heights this past year, as outrage over Freddie Gray's death in a Baltimore police van brought riots, and the fight over how to dismantle prejudice in the criminal justice system heated up in social media. TheLos Angeles Times hired a reporter to cover the social media phenomenon popularly known as Black Twitter (and promptly got criticized for the first story, headlined "When Black Twitter Sounds Like White Twitter"). In Chicago, video of a police shooting contradicted law enforcement accounts and has even led to calls for the resignation of Mayor Rahm Emanuel. Comic W. Kamau Bell even challenged white people to confront the prejudice in Donald Trump's speeches during the year's final GOP debate with the hashtag #WhitesAgainstTrump. Much as people knock social media and online platforms as unsuitable venues for serious discussion, this year offered more nuanced and detailed conversation on complicated issues of privilege and prejudice on the Internet than I've seen in a long while.

4: The year late-night TV was (kinda) reinvented. With Trevor Noah, Larry Wilmore, Stephen Colbert and James Corden all taking over new shows in 2015, a huge chunk of the late-night landscape got re-jiggered. No, CBS didn't hire a woman or person of color to lead its Late Show or Late Late Show after the departures of David Letterman and Craig Ferguson — that would have really been groundbreaking. But Colbert's absurdist, geeky goodwill and Corden's cheeky British charm have recharged CBS' late-night fortunes, even as the genre is increasingly dominated by viral stunts and games in lieu of compelling interviews. At Comedy Central, Wilmore's Nightly Show and Noah's Daily Show are still works in progress, slowly figuring out how to lampoon the day's news in ways that best showcase the new hosts — two black men making late-night history with very different approaches. They are pioneering new voices that give us glorious glimpses of a late-night landscape no longer dominated so completely by white male sensibilities.

5: The year Brian Williams got sent back to the minors. It was the strangest fall of any TV anchor in modern memory. Williams lost his job as anchor of NBC Nightly News for allowing exaggerations told outside the program to seep into one of his reports for the newscast. But by the time NBC announced a plan to feature him on MSNBC after a six-month suspension, Williams had seen his image battered by stories alleging there were other exaggerations and that he had even once lobbied executives to take over the Tonight Show from a retiring Jay Leno. After steady backup Lester Holt barely missed a beat taking over Nightly News — becoming the first black man to solo anchor a network newscast — Williams' departure was more proof that newscasts often transcend the fortunes of those who lead them.

6: A year of departures. There was a lot of loss in 2015, from TV shows that ended their runs, to retirements and beloved figures who passed away. Such losses happen every year, but it seems the TV industry took it particularly hard on the chin in 2015. In TV series, we saw the last of Justified, Mad Men, Nurse Jackie, Key and Peele, Two and a Half Men, The Soup, Parks and Recreation and Parenthood, to name a few. Personality-wise, David Letterman, Jon Stewart, Linda Ellerbee, Bob Schieffer and Willard Scott all retired or left their regular TV jobs. Among those who passed away, Star Trek actor Leonard Nimoy left a nebula-size hole in fans' hearts, along with 60 Minutes ace reporter Bob Simon, play-by-play legend Frank Gifford and many others. In some cases, these losses will reshape the landscape of television. And even in a landmark year when there were more than 400 scripted series made for TV, the industry will have to work awfully hard to replace them.

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