On most projects, you're probably not working alone. That's why Flare has been team-based from day one. Everybody invited to your team on Flare can see all the projects you have in your account.
For small teams, this mostly works fine. When you have a bigger team, people often don't need access to all projects in your Flare account but only a few specific ones they are working on.
That's why we've now added the ability to give team members access to specific projects. In the team settings, you can specify which projects each of your team members should be able to see.
Remember that Flare, as an error tracker, contains potentially sensitive information. So it's also good practice to only expose that information to people who really need to see it.