NOT ON THE LIST IN 2018

ownCloud is an open source, self-hosted file sync and share app platform.

Websites: owncloud.org and owncloud.com
Cost: Free. Open Source
Availability: (Download .org) Commercial (Hosting .com)

Past Overall Rankings
2017: –   2016:178   2015: –   2014: –   2013: –   2012: –    2011: –    2010: –   2009: –   2008: –   2007: –