It should be worth noting that the processor (apparently a Mindspeed Comcerto 2000 (M86261G-12) dual-core ARM Cortex-A9 Communication Processor running at 650 MHz) used on the My Cloud isn’t that powerful, nor is there a large amount of RAM or flash memory on the My Cloud (supposedly 256 MB of Samsung K4B2G1646E DDR3 RAM and 512 MB of Winbound 25X40CL flash).
There is a repository of programs can be added (more or less) to the current V4 firmware: Repository with software worked on v4 firmware
For OwnCloud on the My Cloud, see the following two links…
http://community.wd.com/t/owncloud/91818
http://community.wd.com/t/guide-owncloud/92080
See this link for Clean Debain and OpemMedia:
http://community.wd.com/t/clean-debian-and-openmediavault-on-wdmycloud/93714
Or do a search (magnifying glass icon upper right) of this subforum for the word “[Guide]” for several other discussions on programs added to the existing My Cloud firmware (or replacing the My Cloud OS).