This thread really is divine - it's made by Threadworx in the US and I have it available in the two colours I use over and over for making hearts - Bradley's Balloons (bright rainbow) and Wildflowers (pastel gorgeousness) as well as some other fun colours.
The bright rainbow version is the thread I use to make Dark Hearts, and is the thread included in Dark Hearts kits.
This six-strand thread comes as a 20-yard skein, cut into 20 one-yard pieces. This is the equivalent of a little over 18m total, with each skein measuring around 91cm. With the way I stitch, I get two hearts from one length, which means that once I split my thread, I can make 6 hearts from one thread length and about 120 hearts per skein. Blanket stitch tends to use more thread, so these figures may not work for the blanket stitchers amongst us.