I could break them into four separate categories:
Lotions - quoting Obsidian "has oils, water and emulsifiers. Since lotion contains water, it also needs a preservative." -
perfect! You can easily put lotions into a bottle and use a pump.
Pure Whipped Body Butters - quoting Obsidian "is generally butters and liquid oils whipped into a fluffy consistency" -
exactly!
Body Butter 'lotion' - This is like the kit I did in
this thread. It's basically a 'thick' lotion that you couldn't pump and some are almost in a solid state. The consistency will vary but it's not "whipped".
Whipped Body Butter 'lotion' - this would be where you take the Body Butter 'lotion' and whip it using a mixer to incorporate air to turn it into a fluffy consistency.
At least this is how I've started thinking about them.
I had a blast crafting the body butter kit from lotioncrafters. I highly recommend it. (Thanks IrishLass!)It taught me a bunch about body butters and lotions in general. The finished product is getting excellent reviews from both my wife and daughter. I've tried it too and it's very good and so much easier to use then having to pump a bottle.
The kit was suppose to mimic The Body Shops Shea Body Butter and it does almost exactly, but mine isn't quite as firm as theirs is but the color, smell and feeling on my skin are almost identical.