Six million people are now tracking Pope Francis on his Twitter account @pontifex.
The Spanish version is reported to be the fastest-growing of the account's nine languages, with 2.046 million followers.
The latest of the Argentine pope's 21 tweets since his election was posted last Tuesday.
"Mary is the one who says 'Yes'. Mary, help us to come to know the voice of Jesus better, and to follow it," he wrote.