Fruitarian diet is fruit and seeds based, and may include other foods, and not only plants (e.g. algae, mushrooms) - to answer a few recent questions at once.
Please, do not assume that fruitarianism is eating sweet fruit only. There are many kinds of fruitarians. From those who avoid seeds, if they can, to those who consider honey and eggs to be ethical choices, depending on the circumstances. Usually, fresh fruits are preferable, but the proportion of cooked foods varies. Some fruitarians soak or sprout seeds, some not. Some eat more greens or root/stem vegetables, others prefer botanical fruit, including non-sweet kinds (like tomatoes, cucumbers, squash).
Most fruitarians have ethical or environmental concerns, some may not, health or performance may be their primary motivation. There are frugans, seasonal fruitarians, freegans, raw vegans or vegetarians with high fruit intake, and so on. Everybody is welcome here :)
There is no ideal food or method, there is no competition for higher ethics or better health. The idea is to present this topic to more people for an ongoing public discussion and to share knowledge and experience.