Hey fellow Reddit refugee!
Welcome to one of the best place on the internet.
First of all, I'll direct you to the tribes index, which is the repository of the most subscribed and active tribes. Since the site is separated in categories, there's a whole tech category for you to explore!
Finally, if you get lost or have questions, don't hesitate to ask here or PM me, I'll be glad to help :)

edit: /u/drunkenninja beat me to the punch I see. :P