Over on his blog Sebastian Kügler talks about the status of Akonadi, how the migration of Kontact to Akonadi is going, and in general where the direction of development is leading.
As a status update, sebas notes "Initially, we had planned to release the new Kontact along with the rest of the KDE Applications 4.5. This did not quite work out, so we pushed the release back a bit, and are planning to release it along with one of the 4.5.x updates. The current plan is to release the Akonadi port of Kontact still this year. In contrast to our usual releases, this step is a bit different. We want to avoid hassle for the end-user as much as possible, so we are extending the beta phase until we think the quality is sufficient for the high demands of users, which is especially important in Kontact, where you likely spend a lot of your time."