What is Atlassian? I do not understand?

[Birdhouse Digital]

I'm new to Trello. Why is there logins for Atlassian and when I click to learn more about privacy, view my profile and visibility it's all on this Atlassian platform? It says I have an Atlassian account and that only me and admins can see my email address? Who are these admins? If I signed up for Trello why is Atlassian showing up everywhere and accessing my information? I'm very confused? Is Atlassian some sort of software tool that controls the selling of trello boards? 

[Nic Brough -Adaptavist- · Accepted solution]

Atlassian are the company that own and run Trello.

Trello uses accounts with Atlassian for access, but it's not the only thing that uses such accounts - the Cloud tools they provide can all use the accounts, and Atlassian's non-product systems also use them (including the Community here).  This is the same thing places like Google and Microsoft do - one account is used to access multiple services.

[Birdhouse Digital]

So Atlassian accessing my personal information is not shared out to other Trello board admins/creators that I purchase from, share boards or copy? 

[Nic Brough -Adaptavist-]

Only the information required to use an application is given to it and the administrators of that system (although you can choose to share more of it if you want).  In most cases, it's nothing more than a name and your email address.