Ok so this is my current understanding, please correct me where I err and supplement where I omit needed information.
Historically the Mensheviks and chartists inspired social democracy whereas the Bolsheviks inspired Marxism-leninism.
They (demsoc and socdem) are extremely similar but have some key differences. Social democrats are to the right of democratic socialists and they are both centre-left parties slightly to the left of social liberalism.
left-ish------Center-left----Center
---------Demsoc-----Socdem Libsoc Lib
Where they differ is usually on imperialism and capitalism.
Social democrats typically support imperialism continuing so long as a slice of the spoils support a welfare state. In that sense they're just capitalist reformists. It also appears that the DSA and the "Democratic-Socialist" movement in the United States is simply social democracy with no intention of seizing the means of production.
Democratic socialists do advocate for seizing the means of production and want the end of imperialism but believe this can be accomplished democratically -- however naive that may be.
As far as I can tell social liberalism appears to be almost synonymous with social democracy but with an added emphasis on the "freedom" to own private property and a more laissez-faire role of the state.
Please fill in my understanding :)
Would you count Venezuela?
Not necessarily, for two reasons:
1 is that the PSUV has never considered themselves democratic socialist, their official movement is '21st century socialism'. Chavez had also attempted/participated in a coup in 1992, and though it failed and he eventually won the election in 1998 he allegedly was only convinced of the electoral route on practical purposes.
2 is that I am wary of outsiders trying to fit a mold onto existing movements. We saw this with the Black Panthers (they were apparently every possible shade of marxism) and the EZLN (that anarchists claim are anarchist, and the EZLN saying "no we're not anarchists").
Of course, I support Venezuela in the path they chose. But we still see several contradictions of a dictatorship of the bourgeoisie in the country, and I am not aware that PSUV is trying to overcome them, i.e. making their socialism a transition stage to communism.
fair points. i often hear of democratic socialism in refence to latam elected socialist governments, like Venezuela, or even Allende's Chile.