In a well-functioning Agile development team, the members of the team collaborate in multiple ways during a given development cycle or Sprint.  Coders, testers, designers, and product owners work closely with each other to ensure that the most important features and fixes are worked on in the right way at the right time, also bringing in people from other business or development teams to make certain that the full portfolio of products is growing in ways that support the broader business goals of the company.  In my current firm we sometimes refer to these cross-team groups as TeamNets (see the following link from Amazon.com for more on this: http://www.amazon.com/The-TeamNet-Factor-Bringing-Boundary/dp/0471131881).

Working effectively in these cross-functional teams requires not just a commitment to collaborative development; it also necessitates that each team member understand his or her role on that team and trust that other team members will also fulfill their roles. …