What's a Buddy Quilt?
Buddy Quilt is a quilt made entirely of HSTs (half square triangles) using fabrics traded with other quilters. The only guideline for color placement is "light on top, dark on the bottom" of each HST. It looks like this:

How big is a Buddy Quilt?
As big or small as you want it! You can make a small one for a wall hanging, or a king sized quilt top. But the bigger you want, the more HSTs you'll need!
What's an HST?
Half-Square Triangle. That's what you see in the pic above - a square made of 2 triangles sewn together.
And this is made with exchanged fabric?
Yep! That's the "buddy" part of the name! You exchange 2.5" ("charm") squares with other Buddy Quilt makers. You could make it entirely with your own fabrics, but then it wouldn't be a Buddy Quilt. :)
I know other quilters, but they don't do this / I don't quilt but I love the idea of exchanging fabric / I just think this is neat! Can I still participate?
Sure! If you exchange fabric with other quilters, that still counts as "buddy" fabric, whether they're making a Buddy Quilt or not. And you don't have to make a Buddy Quilt to want to share fabrics with others. If you just want to enjoy the concept and cheer people on, you absolutely can!
Okay! What kind of fabric can I exchange/send?
Cotton fabric (ideally quilting cotton) in 2.5" squares. That's the minimum size. If you want to send something bigger, you can - the quilter can cut it down if need be.
How do I exchange fabric?
You'll need to PM someone else to get their mailing address and give yours. Since fabric is a physical item, this is really the only way to do it. No requirements as to color, print, batik, etc - any cotton fabric suitable for quilting is acceptable!
What can I post?
You can absolutely post pictures of your fabrics and your progress!
You can post a profile of yourself if you like - what size you want, if you want to exchange (or gift) fabric, and whether you'll exchange outside of your country.
Can I use duplicate fabrics?
You can if you want, as long as they're "exchanged" fabrics that you received! Some of us (like me!) are trying to use only one of any given fabric, but you don't have to.
Can I ask other questions in the community?
Sure! Welcome! :)