I feel funny about gelatin (jello makes me feel all wobly inside), but I can't say if it's because of the wobliness or the fact I'm always afraid it's gonna be animal gelatin which grosses me out for some reason.

Actually, does anyone know if this is commonly used, or if supermarkets/companies still mainly use animal gelatin?

I've heard about how gelatin is made and it creeps me out. (I'll still eat it though.) Anywho, agar agar is good if you want to make something that's a bit firmer than jello.

agar agar is also useful as a thickener for sauces, savory ones included

Sounds disgusting. I work in science, and we use agar to grow bacteria for experiements!

Would this work as a direct replacement for gelatin? I've been looking to make some homemade marshmallows but feel a bit icky about using gelatin from my local supermarket, being a vegetarian!

agar, haha. i use this every day in my lab.

I used to have agar all the time when I was younger as a gelatin type dessert. Of course, it was flavored, but I always enjoyed it a lot.