I usually explain the split like this: OpenOffice was a cooperation between about 1000 corporations and unaffiliated individuals. When Oracle bought Sun, the largest contributor at approx. 25%, they essentially said "my way or the highway", so the remaining 999 left, but took the code with them and started LibreOffice instead. Since then LibreOffice have been getting about three times as much development compared to OpenOffice, so use LibreOffice instead...