Blob is a View Mode in OE-Cake; the first mode that does not show individual particles, rather it treats material as 'blobs', hence the name.
Blob mode, note the translucent gas particles and the fire effects.
It also shows extra effects for Fire and Gas-based materials. It is the most commonly used mode alongside Shader.
Blob and Texture is the same as Blob but allows pictures (textures) to be visible.