ECO is a cooperative project to digitize historic volumes of Canadian interest. The most fruitful part for genealogy, called "Early Official Publications", is available only by subscription. Its also the largest and most frequently augmented. Amongst the interesting odds and ends are Civil Service lists (detailing the thousands of Canadians employed by the government from 1885 to 1900); information on people receiving awards, pensions and with an interest in certain companies. There is also a collection of guides for prospective immigrants to Canada and select speeches of John A. MacDonald and others. See a list of recent additions at <>. Its amazing what treasures sometimes turn up.
Subscriptions at $400 are hardly affordable for the individual genealogist, but some may be able to benefit from access at a local university or public library where the annual cost is $70 per 11,000 residents served. Ask your library system to subscribe if they don't already.
Much of the content in the free section is of limited interest for family history. There are sections on Canadian Women's History, Colonial Government Journals, The Early Governors General of Canada, English Canadian Literature, History of French Canada, Hudson's Bay, Jesuit Relations, Native Studies, Reconstituted Debates.