Neither are "special interest groups". They are both associations with members who are songwriters (SOCAN) or musicians (ACTRA) who have assigned them rights to manage their authoring/composition (SOCAN) and "performance" (ACTRA) royalties.

Both take administration fees from royalties collected but are not-for-profit (or at least I believe this is how they are both defined).

More than not quite. More like completely different than MPAA and RIAA.

As stated above, SOCAN is a performing rights organization. Specifically they handle the authoring and composition royalty of a piece of music. So I write a song, I become a member of SOCAN (as a Canadian), they track the usage of that song (typically radio play only) and they pay out a royalty for the authoring (lyrics) and composition (music) of the song.

ACTRA represents musicians to broker the royalties as they relate to (what is defined in Canada as) Neighbouring Rights (http://www.nrdv.ca/) which is essentially the "performance" of a recorded piece of music. So I play as a musician on a recorded piece of, it gets played (again, typically on the radio) and they pay out based on my performance on this piece.

This later concept differs greatly in the US, where terrestrial (AM/FM) radio does not owe "performance" royalties. SoundExchange via a whole heck of congress lobbying is the closest equivalent to ACTRA (or the two other Canadian associations that deal in these royalties), however, it only deals in Internet streaming and satellite radio. And, yes they totally fucked up.

SOCAN and ACTRA have historically helped to look after the little musicians. They are not inherently evil despite what the likely opinion on slashdot will be.

Now, as a musician, in Canada, who writes songs, gets airplay and, yes, has leftish values, I think that this is an acceptable compromise. Bars, restaurants, dentist offices, etc all get surcharged for playing music in Canada at their workplaces (as music is seen to add value to their business). The same argument can apply to ISPs who have more demand/usage by people looking to listen and become exposed to music. I think ultimately the impact to consumers will be negligible in terms of a rate increase (which is likely to be also monitored by the CRTC).

... so they get the girls!