Someone will correct me if I am wrong but BOM is just a new block pattern every month for you to try something new for your own personal quilt. It is not an exchange.
However there are several different exchanges that you can get in on and some of them start in January such as Doll Quilts, the quilting bee block which is when you pick a theme/color combo and then you get a new partner every month to exchange blocks--you do one in their theme and they do one for you..it is fun! There is also a 12 block exchange in January in the colors of raspberry and chocolate...you make 12 blocks in those colors and then send them in..then you will get your block back plus 11 different others so when you get them back you have enough for a sampler quilt.
SO you will just have to navigate through all of the forums and see what suits you best! Have a great time!