A wonderful resource on the different types of sex acts and kink acts. You can drop "pins" to indicate areas that interest you or that you have tried previously. A great conversation starter with kinky friends, and the link to your personal map can be copied and pasted onto your Fetlife profile!
A resource from UberKinky, the Periodic Table of Kink offers an interesting way to categorize kink activities as well as a look at things you may never have heard of before!
Fetlife is the premiere "social" site for kinksters to meet, connect, plan live events, communicate, and collaborate. Pay special attention to the "groups", as there are opportunities to learn about everything from local munches to kinky furniture building to places for outdoor primal scenes.
IMPORTANT: Fetlife is NOT a "dating" site, and it is generally considered rude to use it as such. Expecting to use Fetlife as a "kinky Tinder" will result in a poor experience.