Here is the information that I received:
"Hiya, Thanks for contacting me!
I don't get many e-mails through Flickr so its great that you have e-mail me

I've been playing Teen Second Life since October 2006, I've made many friends and i'm well known both in TSL, RL, TSL Forums. Teen Second Life is for Teens 13-17 once they turn 18 years old from what I've heard they have to send in a picture with ID to Linden Lab then they get transferred to the MG. However before they leave they can choose to have a party and make finally choice if chosen to do so to come back to TSL as a approved adult on one of the educational islands e.g. Global Kids, Eye4you Alliance etc.
When they turn 18 they will be moved to a welcome area on the Main Grid Transfer Station before they visit anywhere on the main grid and could be put into a bridge building group or Teen Transfers Group by LL to welcome them onto MG etc.
How it works:
1. Teens keep all their content in their inventorys when they move up to MG
2. Their friends list gets cleaned/deleted > so they would need to email each other or find each other when they leave tsl for example
3. Teens will be moved from the Teen Grid name database after time
4. Teen Group list that a teen is in will be deleted > start all over again i have heard
5. Teens can transfer their island to the MG if they have brought one but they cannot transfer a rented or land brought on mainland
6. Be moved from the TSL Forums to MG forums
7. They will have to find new friends, explore new places, make stuff, join in or make events etc when they come to the MG
8. Griefing in TSL is the same as the MG however LL closely watches it more, but can be dealed with by reporting abuse, nothing really seems to be done about it.
I've had some friends move to the MG lately, i keep in contact through skype etc and they said that they want to come back to the TG as they miss their friends alot and also they hate the mature stuff on the MG. Also they don't play as much on the MG then they used to when on the TG. However some of my friends say is awsome!
For me i can't wait to leave TSL, it sounds awsome so much to do and stuff.
CHECK THIS OUT!
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You can visit my Blog for more info - look through my pages!
danielvoyagerwebsite2008.wordpress.com/
My TSL Flickr
www.flickr.com/photos/danielvoyager
My SLUniverse Images
www.sluniverse.com/pics/Default.aspx?Name=Daniel+Voyager
My TSL Mentor wiki
wiki.secondlife.com/wiki/Daniel_Voyager
From Daniel Voyager - TSL Volunteer
(please spread and pass on my links)"