When sketching concepts in the very early stages, many designers are merely exploring. Part of this exploration might be guided by parameters, perceived requirements, content specifications, etc. Early sketching should be a mashup of platform or device formats, icons, type, interactions and other visual tid-bits. But this stage is also the stage for documenting general thoughts as well. These may or may not be visual. They can be notes, thoughts, words, hex values, directional arrows… actually anything. I have found that early ideation develops at a faster pace and with greater success when designers get everything out of their head and onto the paper. It can be a mess – but a beautiful mess. It is a journey of creative thinking and trial and error.