By PETER BAKER

WASHINGTON - Anthony Lake served as one of Barack Obama’s principal counselors on foreign affairs during the campaign and exchanged e-mail messages with him regularly. But now that Mr.Obama is president, Mr.Lake no longer has his e-mail address.

“No,”he said when asked if he had it.“Did. Don’t.”Neither does Nancy Pelosi, the speaker of the House, nor Steny H. Hoyer, the majority leader, but they do not use email much anyway. Mitch McConnell, the Senate Republican leader, is a BlackBerry devotee, but he does not have Mr.Obama’s address. Nor do many members of the cabinet .

Vice President Joseph R.Biden Jr. has it, along with his own new super-secret BlackBerry and e-mail address. So do Mr.Obama’s chief of staff, his top advisers and some of his oldest friends from Chicago.

It is now the ultimate status symbol in a town obsessed by status. Mr.Obama was spotted late last month trying out his new BlackBerry? or actually a more sophisticated, encrypted variation? and aides say that he uses a computer in the study next to the Oval Office but that he has agreed to limit the number of people he would exchange e-mail with. In the process, he created a new measure for Washington to judge who really has the ear, or the thumb, of the president.

For decades, the capital scoured state dinner invitation lists and Camp David visitor logs for clues to who was in and who was out. Now there is President Obama’s e-mail, the first used by a commander in chief while in office.

“This is the 21st-century version of the same special access that certain people are always granted to the president,”said Joel P. Johnson, a senior White House adviser under former President Bill Clinton.

Mr.Obama joked about the exclusive nature of his e-mail list at the annual Alfalfa Club dinner in Washington on January 31.“How exclusive?”the president asked.“Everyone look at the person sitting on your left. Now look at the person sitting on your right. None of you have my e-mail address.”

Security personnel worry that the more available his address, the more vulnerable it may be to hacking pranksters or, worse, to cyber-attackers from, say, Russia or China.

Mr.Clinton never became interested in e-mail while he was president and former President George W. Bush gave it up in the Oval Office on the advice of lawyers.

John D. Podesta ran Mr.Obama’s transition and exchanged e-mail with him virtually every day from the election to the inauguration. But he does not have the new address.“Some things are secret,”Mr.Podesta said, although he added,“My guess is the list will grow.”