Pope Benedict XVI is due to send out his first, much-anticipated Twitter message on Wednesday, with hundreds of thousands of followers already signed up to receive the tweet.
Since the pope last week announced he would start tweeting under the name @pontifex, around 625,000 people have registered to follow his main account, in English. Tens of thousands more are following his Arabic, French, German, Italian, Polish, Portuguese and Spanish accounts.
The first tweet is expected around 1100 GMT, marking a milestone in Vatican communication efforts as it tries to disseminate the Catholic message -- especially to younger people.
"The first tweets will be answers to questions sent to the pope on matters of faith," Vatican communications adviser Greg Burke said last week, inviting users to ask questions of the pontiff.
Several fake Twitter accounts have already been set up in the pope's name and used to mock the 85-year-old pontiff. Burke said there would always be parodies, as well as tweets that seem official but are fake.
Thousands of people in the Twitter universe have posed questions to the Church, including a slew of offensive and negative messages referencing the clerical sex abuse scandals that have rocked the Church over the past decade.
Burke, a former correspondent for US channel Fox News brought in by the Vatican in June to overhaul its public-relations operation, has said the pope's Twitter account would create "a free market of ideas, and that is good."
The 140-character messages will not be written by the pope himself, but by Vatican officials who will submit them to him for approval.