Except the very act of registering the birth would have generated the birth announcement. As was stated upthread the address associated with the birth announcement was NOT associated with the Dunhams or Obama Sr. Also please note it does not specify where Jr was born!
I beleive you are incorrect about BO not living at that address.
http://www.honoluluadvertiser.com/article/20081109/NEWS01/811090361/0/NEWS01
The future president’s first boyhood home is still standing on Kalaniana’ole Highway, in the Kuli’ou’ou area between ‘Aina Haina and Hawai’i Kai.
The yellow, four-bedroom, single-story home was built in 1948. Nani Smethurst, who has owned the home since 1979, said the place is essentially the same as it was when it was built, although it has been upgraded and landscaped by Smethurst, who is an architect.
The property also has a 450-square-foot cottage in the back that was built in 1953.
Smethurst said she recently noticed people coming around to peer at her home. Then she began receiving calls from local and Mainland newspapers inquiring about Obama’s first home.
“I didn’t know,” Smethurst said. “And then we got a call from someone saying did you know your home is Barack Obama’s first home. It seems that somebody knew. A lot of people, when passing through, would come take a look and maybe take pictures.”
She said someone posted the address on the Internet. That July posting contained a photocopy of what is most likely the first mention of Barack Obama ever published — a tiny, one-line birth notice in the Sunday, Aug. 13, 1961, edition of The Honolulu Advertiser:
“Mr. and Mrs. Barack H. Obama, 6085 Kalanianaole Highway, son, Aug. 4.”