The announcement saw ANC president Jacob Zuma re-elected for a second term, with Cyril Ramaphosa his deputy.
After the announcement Mazibuko posted on Twitter: "Poor old Forces of Change. Though nobody could claim to be surprised by this result. ANC had real chance to change SA in Parliament and blew it".
@marupta tweeted DA leader Helen Zille and Mazibuko, asking them how much one should pay to become a member, adding: "It is time I stop voting on history but on good of the country".
Mazibuko replied that it costs only R10 to become a DA member.
@MoMadiba tweeted: "Where can I join in Soweto?", to which Mazibuko referred her to someone who could assist.
The DA leader assisted many other people inquiring about where in their areas they could be assisted to become DA members.
At one point Mazibuko's twitter account was so busy that she was trending in the whole country.
Lindi Mashinini tweeted: "You have my vote! I am not voting for Zuma as my president in 2014! For the first time in my life I am ashamed of the ANC!"
@newageadam suggested Mazibuko take out a newspaper advert in Sunday papers with the Gauteng branch's contact details.
Mazibuko thanked DA officials for responding promptly to her twitter referrals.
The DA City Bowl branch also tweeted that their inbox was "overflowing with people keen to join the DA".
DA spokesman Mmusi Maimane said he was also flooded with requests on how to join the party.
"It's an indicator of the fact that the ANC chooses a leader for itself and not one for the country," he said.
He said it has proven that South Africans think there are two parties in South Africa and that when the ANC cannot get something done then they look to the DA because "there is no other party that is taking on the struggle as they are".