Behind the headlines, The Associated Press wrestles with bizarre administrative hurdles and jaw-dropping contradictions trying to use the law; some recent ones are described below.
Mr. Obama has begun to deliver, but there are conflicting signs about how far he will go.
On his first day as president, Mr. Obama told all federal agencies to adopt a presumption of disclosure - reversing the Bush administration policy of defending any legitimate excuse to withhold information.
This month, the Justice Department released nine legal opinions the Bush administration had used to justify its tactics in fighting terrorism but had withheld from the public. The papers showed that lawyers for the Bush administration once argued U.S. troops could pursue terrorists inside this country without obeying the Fourth Amendment ban on unreasonable searches.
But three dozen more Bush-era legal memos about anti-terrorism tactics are still kept secret, the subjects of lawsuits by private organizations trying to obtain them. The memos include the justification for wiretapping Americans in this country without court approval.
The Justice Department is writing new guidelines to flesh out President Obama's policy. One key question: How far will the new administration go in reconsidering the Bush administration's refusal to release documents? In a few pending suits so far, the Justice Department under Mr. Obama has opposed or rejected delays to give it time to do just that.
The act has required the government keep secret records that might harm national security, disclose the identity of law enforcement informants, compromise a criminal investigation or reveal trade secrets of corporations. There's no opposition to those exemptions, but people argue over how they are applied.
The act also gives agencies discretion to withhold other materials, including records about internal policies the agency considers trivial or working papers written before a final decision is made. It requires agencies to balance the public interest in disclosing some documents against the privacy rights of individuals who might be named in the documents.
As the world's largest news organization, the AP files hundreds of requests for government records each year. The documents it collected from the federal or state governments helped its reporting on:
Sometimes, the AP's efforts at using the Freedom of Information Act are less successful. From inside the working files of AP reporters, here are some of those recent cases:
Classified, Still: The CIA is trying to protect secrets, long after they no longer are secret.
The government's chief spy agency in December censored copies of 1960s-era documents the AP requested about former President Gerald Ford's work while still a congressman reviewing President John F. Kennedy's assassination. Citing national security concerns, the CIA censor blocked out parts of a memo written 45 years earlier by a senior FBI official, Cartha "Deke" DeLoach.
Trouble is, under a law making records of the assassination public, the government released the whole memo nearly two decades earlier - without blacking out the parts the CIA still doesn't want people to see.
The censored memo was turned over to the AP within FBI files released about one year after Ford's death. In the uncensored version, Ford described hearing a CIA report that Lee Harvey Oswald received $6,500 from the Cuban consulate in Mexico City. "Ford stated this excited him greatly in as much as it definitely tended to show there was an international connection involved in the assassination of the president," DeLoach wrote.
The CIA blacked out the entire passage about the tip, even though it has since been debunked among JFK scholars. The memo included DeLoach complaining that the CIA source had told conflicting stories.
"It's just astonishing that would remain withheld. That information was out so long ago," said Jim Lesar, a Washington lawyer and JFK expert. "It just indicates there's no rhyme or reason to what they're doing. You get people deleting things totally inconsistently."
Penny-Wise, Pound Foolish: Why spend 42 cents when you can spend $10 and complain you're short of money?
The Labor Department pleaded poverty in a letter to the AP this year, saying it didn't want to spend money on a request for records that might be no longer needed.
The letter came nearly two years after AP requested copies of correspondence from the candidates in the 2008 presidential campaign. The AP asked for speedy handling - as the act allows - so it could get the materials during the White House race. In its letter, sent months after the election, the Labor Department said, "In light of the number of appeals pending in this office, we do not wish to expend our very limited resources on matters which are no longer of particular interest."
But the department was willing to spend its limited resources on Federal Express. Rather than buying a 42-cent stamp and mailing its letter across town - or e-mailing or faxing it - the department's one-page letter was delivered by Federal Express. The rate for an in-town, two-day delivery: $10.50.
DeLay-ed Reaction: The Treasury Department took four years to respond to AP's request for correspondence from disgraced lobbyist Jack Abramoff or Republican Rep. Tom DeLay, just one of the powerful lawmakers Abramoff courted. By the time Treasury responded to AP's request, Abramoff had been sent to prison in another case, and the scandal-afflicted DeLay had left office after long ago losing favor with Republicans.
A Slooooow Revolving Door: When he became President George W. Bush's new spy chief early in 2007, retired Vice Adm. Mike McConnell quit his $2 million-a-year job at Booz Allen Hamilton Inc., a large defense and intelligence consulting company with sales of $4.1 billion.
More than two years later, the AP is still waiting for those files. Others are waiting on the spy chief's office for their records requests, too. Its latest annual FOIA report listed at least 10 pending requests older than the AP's.
And McConnell? He served two years as intelligence director then left government after President Obama took office in January. He returned to Booz Allen.
Beat The Rush: Is it urgent if no one else knows about it yet?
AP reporters often ask for a speedier-than-usual response when documents might relate to a breaking news story. That "expedited processing" is allowed when a reporter can demonstrate some urgency to inform the public.
Widespread backlogs make it necessary. At the Homeland Security Department, for example, it takes 58 days on average to respond to an expedited request. Regular processing averages 146 days for a simple request and 280 days for a complex one.
Despite President Obama's promises, Homeland Security came up with a new reason last month for rejecting an AP request for a speedy response. The department said the AP's material couldn't be that urgent because it was the only news organization to ask for the documents so far.
That excuse "completely lacks legal merit," said Karen Kaiser, an FOIA lawyer for AP. "Expedited processing is not evaluated based on the number of requests an agency receives for a given document but upon the urgent need to inform the public about government activity."
Redacted: Fifteen years, a best-selling book and a hit movie haven't persuaded the Pentagon to release all the details of the Battle of Mogadishu, a tragic operation in East Africa that cost 18 American troops their lives and Clinton administration Defense Secretary Les Aspin his job.
Better known as "Black Hawk Down," the title of journalist Mark Bowden's 1999 book and the film that followed, the battle took place in the slums of Somalia's capital city in October 1993.
A detailed report based on accounts from commandos who were there was completed in June 1994. In August 2007, the U.S. Special Operations Command rejected AP's request for the document, which it said was "properly and currently classified."
AP appealed. Last month the Pentagon released a copy with all but nine of the 73 pages blacked out. Most of the information remains classified, the military said, to protect military plans, weapon systems and the privacy of individuals involved.
"Why do they keep these things secret?" Bowden said. "The answer is, because they can."
By Reason Or Rote?: Some decisions to keep information secret are just puzzling. The Homeland Security Department sent the AP stacks of papers over the past three years in response to one request. Included were copies of e-mails the AP reporter had sent to Homeland Security officials about the subject of the request. To protect their privacy, the government blacked out some of the names and e-mail addresses of the officials to whom the AP reporter had addressed his e-mails.