It is possible to see the foundations of the
modern eBook from such activity, as the
necessity for reflowable text when reading on a Portable Digital Assistant (PDA) led to the formation of the Open eBook Publication Structure (a precursor to the EPUB format) in 1999, and several portable devices such as the
Game Boy Advance, PalmPilot and SoftBook had facilities
for modems, allowing readers to receive books without using a computer, often seen as one of the core selling points of the original Kindle.