What is retracker?

[F89Traktor]

Good morning!
My question is about "retracker". 
I went to the same seeddbox company I was six months ago and all torrents I add contain an unusual IP address first in the trackers list of all the torrents. Searching in the ruTorrent settings I found one named "Retrackers" containing an announcement "http://xxx.xxx.xxx.xxx:6969/announce" which is the one added to the torrents and a checkbox with the phrase "don't touch private torrents" at the upper side of the preferences window.
Can someone explain to me what is this and what's the gain for me or anyone else?

Thank you!

Manos

[mair.nl]

  I misunderstood earlier, Here you can add aditional tracker url's you may want to use on all your public torrents

[F89Traktor]

I asked the same question to the company to receive following answer:

It's adding for example public tracker url to all public torrents you've added . This way you don't have to manually add them if you wish to seed them on some additional public tracker.

The problem is that I must learn things on "how networks function"...

[mair.nl]

I misunderstood earlier, Here you can add additional tracker url's you may want to use on all your public torrents