According to http://pencils.com/why-are-pencils-yellow/, the pencil has been yellow since 1890s, although the Chinese and Americans used graphite to make the pencils.
Personally, I honestly don't like wooden pencils, because they constantly break, while pens and mechanical pencils don't. I prefer pens, because the ink doesn't actually disappear, or get smudged. I try not to be a pencil doodler, but I often get bored, so eventually I do end up doodling. I kind of think we will use pencils, because it'll remind of the old age, and also the yellow pencils are longer and easier to use, (depending on who you are.)