Al Jazeera America launched at 3 p.m. ET Tuesday. Here's a quick primer:

It may be a unicorn: "[T]here's an undeniable fascination in watching a giant news outlet come together in a matter of months," Joe Pompeo wrote in July about Al Jazeera America's planned launch. "It feels something like witnessing the birth of a unicorn: staggering, illusory."

But although the network hired many journalists to get ready for its launch, the process represented a job market that's not so fantastic. Al Jazeera received more than 18,000 applications for 170 jobs, Tracie Powell wrote in March, and had looked at more than 21,000 applications for 400 positions by the time Pompeo's report hit.

It faces higher bars than many new media ventures: Al Jazeera America replaces Current TV, which "had about 24,000 viewers in prime time" last month, Brian Stelter reports. And the network, funded by Qatar's government, follows previous attempts at getting the channel Al Jazeera English onto cable-company channel lineups. Time Warner Cable dropped Current after Al Jazeera bought the network in January. The network's name "still arouses deep suspicion in some Americans, mostly because of the period immediately after the Sept. 11, 2001, terrorist attacks, when Al Jazeera broadcast messages from Osama bin Laden and was demonized by Bush administration officials as anti-American," Stelter wrote.

It's investing in American bureaus: “We are going to be committed to covering news that comes from all over the United States in ways that our competitors can’t do at this point,” Al Jazeera President Kate O’Brian told Dylan Byers. In addition to cities like New York, Los Angeles and Washington, Al Jazeera America will staff bureaus in Seattle, New Orleans and other cities. Jonathan Martin, who is heading the network's Nashville bureau, told Jamie McGee of the Nashville Business Journal the network's presence "means more coverage for Nashville stories, pointing to the May 2010 flood as an example of a local story that could have benefited from more immediate, national coverage. This week, for example, he was able to quickly turnaround a story on the indictment of the Vanderbilt football players from Nashville."

It's made some interesting hires: Joie Chen, Soledad O'Brien, John Seigenthaler, Ali Velshi and David Shuster are among the on-air talent.

You won't be able to watch online: Al Jazeera America had to agree to block U.S. viewers from its online streams to appease cable companies, Stelter wrote. It will feature about six minutes of commercials per hour.

It's offering straight news. Does anyone want that? The channel will offer "less opinion, less yelling and fewer celebrity sightings.” acting CEO Ehab Al Shihabi said. "If the audience for a channel like Al Jazeera America does exist, AJAM so far has done little to court it," Byers wrote. "This is your chance to reinvent TV news, not copy it!" media critic Jeff Jarvis wrote. "I'd rather they listed lots of shows and then said, 'Ours will look and sound nothing like them!'" Here's Al Jazeera America's values statement.