There are some rumors that LibreOffice and Thunderbird may unite their forces in order to try to compete with Microsoft’s Office and Outlook projects. An unofficial wiki puts together all the ideas proposed so far, and the collaboration between the two is one of them.
Despite the fact that Thunderbird has been developed by Mozilla, the development has been dropped and the community and the volunteers are currently maintaining the email client.
Thunderbird, considered a PIM (personal information manager) software, provides email address book, calendar and tasks would become an important component if integrated in the LibreOffice suite.
We will keep you posted as soon as we find more information about this.