They can be similar in a few ways, but they are actually structured differently.
With capitalism, private ownership of industries and services remain dominant (Even with high taxation).
With socialism, the state controls major industries such as energy, healthcare, transportation, etc..., although there can still be private ownership in smaller sectors and some market activity.
In short: high-tax capitalism is still capitalism — the government just takes a bigger slice of private profits to fund social programs.
Socialism changes that foundation, going a bit further by the government (or society) owns the means of production directly for most goods or services.
The end result of either is redistribution of wealth, so in that way, they are alike. It's just state ownership that is more prominent in socialism.
There seem to be varied usages of the word "socialism". The one you provided,
@bobcat, isn't how a lot of Canadians understand it, even if they (as individuals) view themselves as socialists. I think some (possibly a majority?) of Albertans might agree with your definition (because they sternly oppose government of the sort you described). But the overall situation in Canada could, I think, be described as social democracy (some might like "democratic socialism"). I'll share a few aspects.
Here the majority of enterprise is not in the hands of government. True, we have socialized medicine (operated by the provinces, with differing details,
not by the federal government). We have one petroleum company (PetroCan) that the feds run, and several other common ones that are ordinary business systems (Shell, etc). And there's one in the western provinces (Federated Co-op) which is owned by citizen members and, separate from government, holds elections for management at each level from top to bottom.
In my province (British Columbia) we have a provincial transit system that serves cities & towns. We have freight rail run as profit-oriented enterprise, and a passenger-rail system (Via Rail) owned by the federal government. Where I live, the provincial highways and roads were formerly maintained by a government department, but this was privatized decades ago. Outside of Canada Post, most trucking in this country is operated by private companies. My province has an automobile-insurance system, and many people use this — but there are privately owned/operated systems you can choose if you want.
We have many
private radio and TV networks, and one national network (CBC) owned federally (but the TV version has paid private-sector advertising); plus numerous communities have
local citizen-supported co-op radio stations, in addition to conventionally owned ones.
We have three main political parties at the federal level
: the Conservatives, the Liberals, and the New Democratic Party who have completely social democratic principles. At the federal (and in Quebec itself), there is also the Bloc Quebecois. In the provincial level (except for the Bloc Québécois) things are similar. Some responsibilities & services within the country or the provinces were government operated at one time, but due to policy shifts have been privatized.
I believe our country is more 'socialistic' than the Netherlands, but less so than Finland, Sweden and Norway. And our system does not at all resemble those of China, Cuba, or the bygone Soviet Union.