Definition:
Martin Fowler proposed the term “Seeding Visits”, one of the most popular approaches to getting together. He says, these should occur early in the project and are intended to create the relationships. A seeding visit that brings all team members together at the start of a project can be one of the best possible investments in the success of the project. This is important for projects on which team members do not know each other, have minimal shared history, distributed across the geography having different languages coming from different cultures.
This face-to-face kickoff gives an opportunity to meet each other, establish a rapport, and understand the project together. One release cycle is beginning, the preceding one is ending. This is an ideal time to bring a team together. Teams can be colocated for the vision-setting and planning of the new release, for reviews and retrospective. Bringing the team back together for the last couple if iterations before the final release makes the process of shipping a final deliverable much smoother. Bringing the whole team together, helps in making key decisions.
Further Reading:
Book: SUCCEEDING WITH AGILE Software Development Using Scrum by Mike Cohn