From NBC's John Yang

According to several gay rights activists, who have been briefed by the White House Counsel's office:

The memorandum President Obama is signing today will not create benefits. It will direct all agencies to report back to the Office of Personnel Management on the things they can do within the constraints of the Defense of Marriage Act and, presumably, implement those changes at the end of the review period.

Video: Gay and lesbian activists have been seething over what they see as President Barack Obama abandoning his promises to the community. A political panel discusses what Obama can do to fix this problem.

DOMA prohibits the federal government from granting same-sex couples benefits that, by law, flow from "marriage" or are granted to a "spouse" -- health benefits, for example. There are some benefits that law provides to "families" or "children" -- leave to care for a sick family member under the Family Medical Leave Act or long-term-care insurance. It's the second set that the president is moving today to grant.

*** UPDATE *** 'First brick in paving': Here's the statement from the Human Rights Campaign's Joe Solmonese:

"Today's Presidential memorandum committing to a federal workplace free from discrimination, including the extension of some benefits to same-sex partners of federal workers, is a welcome and long-overdue step toward bringing the government's policies closer in line with what America's largest companies understand is good for business. Today's presidential signature is the first brick in paving what is a long path toward equality for gay, lesbian, bisexual and transgender Americans. We commend President Obama and his administration for taking this beginning step to level the playing field, but we look forward to working with him to repeal the Defense of Marriage Act, overturn 'Don't Ask, Don't Tell' and guarantee the entire American workforce is free from discrimination."

The group has been working with the administration on what it's doing today for months, according to one activist. The criticism over the last five days after the Justice Department brief in Smelt and Hammer v U.S. speeded things up.

"We're in a relationship with this administration," the activist said. "Like any relationship, some days are bad -- and you get a brief defending DOMA, and some days are good -- and you get things like today. But at least we're in a relationship. Under the previous administration, it was eight years of solid opposition."