What is the difference between "serger thread" and regular thread for sewing? I saw it on sale at Joann's this morning.

I haven't pieced with it but I have quilted with it and very good results

I use it all the time for piecing with no problems.

I have had no issues with the thread on anything I have used it on, piecing and quilting. I think the serger thread has some polyester in it but it works and is a better value for my money. I have also used the Egyptian cotton thread from Connecting Threads, no difference, no issues.

Thanks everyone--I KNEW I should have bought it!!!!

The biggest difference is that serger thread is finer; because it needs to go through a number of different guides, any roughness would quickly create problems, either snagging on those guides in short order or gumming up the sewing machine. Because of this the individual filaments are also longer than normal, being more evident in the difference between inferior and superior quality threads; a shorter filament is more likely to break away from the main thread than a longer one. Even the twist can create potential problems; an inferior thread has areas where it is thicker or thinner thanks to the twists in the thread, and these small differences can create issues of their own.

Sewfine

I used serger thread from Joann's to quilt a denim quilt. I am a little disappointed with how it has worn. It is a quilt I made to protect my bedspread from the dog. I am including a photo of the result after a few months on the bed, a closeup of the result. The fabric came with embroidery already on it, so ignore that. The lighter blue fuzzed thread is what I'm referring to. I used my embroidery machine to quilt in some of the squares, and a Singer 301 to do the straight stitch quilting. Strangely enough, only the quilting done with the embroidery machine fuzzed.

somewhere else I read that serger thread was thinner and would not endure as well.

I was told serger thread isn't as strong as regular thread. I guess that's why I decided not to use it and just save it for my serger.