As of Feb. 15/17, 404,164 of 640,000 files are available online in the Personnel Records of the First World War database. Please visit the Digitization of the Canadian Expeditionary Force Service Files page for more details on the digitization project. Library and Archives Canada is digitizing the service files systematically, from box 1 to box 10686.
The most recent addition takes the digitization to Box 6831 and last name McGee.
Caveat: The files are not in strict alphabetical order, so if your ancestor's name is missing from the files that have been digitized, the papers may be in a different box not yet completed.
I am anxiously waiting for McGinnis, Peer, and Vollick! Not much longer though and meantime I'm enjoying browsing through the papers.