An agile team in a Scrum environment often still includes people with traditional software engineering titles such as programmer, designer, tester, or architect.
But on a Scrum team, everyone on the project works together to complete the set of work they have collectively committed to complete within a sprint, regardless of their official title or preferred job tasks.
Because of this, Scrum teams develop a deep form of camaraderie and a feeling that "we're all in this together."
When becoming a Scrum team member, those who in the past fulfilled specific traditional roles tend to retain some of the aspects of their prior role but also add new traits and skills as well. New roles in a Scrum team are the ScrumMaster or product owner.
A typical Scrum team is three to nine people. Rather than scaling by having a large team, Scrum projects scale through having teams of teams. Scrum has been used on projects with over 1,000 people. A natural consideration should, of course, be whether you can get by with fewer people.
Although it's not the only thing necessary to scale Scrum, one well-known technique is the use of a "Scrum of Scrums" meeting. With this approach, each Scrum team proceeds as normal, but each team identifies one person who attends the Scrum of Scrums meeting to coordinate the work of multiple Scrum teams.
These meetings are analogous to the daily Scrum meeting, but do not necessarily happen every day. In many organizations, having a Scrum of Scrums meeting twice a week is sufficient.
The illustration below shows how a Scrum of Scrums facilitates cross-team coordination. Each circle represents one person on a Scrum team. The bottom row of this illustration shows teams with eight or nine members on each. One person from each team (the shaded circle) also participates in a Scrum of Scrum to coordinate work above that team. Those teams further coordinate their work with a Scrum of Scrum of Scrums.