I have read that these techniques differ.
In side drifting the oarsman (or kicker motor) keeps the boat at half the current speed while the angler(s) fish through the holding water. Boondoggin is essentially the same principle except the boat is traveling with the current speed.
My sources are a bit dated and it seems that people nowadays refer to boondoggin and side drifting as the same technique.
Does anyone have the answer to what term means what?

Don't over think it,your just draggin bait on the bottom of a river.Some times a little down stream of the boat most the time straight out from the side of the boat a some times behind or up stream of the boat.Good luck,
SZ

same, used interchangeable


check this out....

http://fishwithjd.com/2006/01/10/boondoggin-for-steelhead/

or this one

http://www.steelheaduniversity.com/side-drifting.htm

Boondoggin

The above colloquialism was made popular by a mispronunciation by Larry Schoenborn formerly of Fishing the West.
The technique was to follow, chase, hound log booms (log rafts) in hopes of encountering aggressive fish that had been stirred up by the log boom. Some of these booms dragged ship's chains to control the swing of the rear of the raft if they were being towed.
So, boom dogging would have been the original phrase.
It's anybody's guess as to how much boat control these early guys applied. I would think that some learned to slow the boat to current speed for a natural drift as opposed to dragging.


Side Drifting

Drifting bait to the side of the boat at a natural pace.
The earliest form of this technique that I'm aware of is what was called "rolling shot" on Southern Oregon/NoCal streams.

Edit:
Armed with the above information and about $2.75 you can get a cup of coffee. (not at SB's)

Every river and every hole sets up differently. Beit - line angles slightly down stream, middle of boat or upstream it's all about the captain keeping the baits at current speed and on the bottom. If you're not feeling the bottom, chances are you are not catching steelhead....

Me and the buddies utilize the term "drifting"...

Keith

I've caught fish both ways but not enough to know if one is more effective then the other. A lot depends on the type of structure your fishing I think too. Boon dogging(with the bait dragging behind the boat) seems to eat up a lot more gear in snaggy rivers for me. Although if I had to guess I'd say I've had slightly more action boon dogging then side drifting. Side drifting is sort of like drift fishing with a super long drift. The most common technique I've used is the fast walking drift as I'm not lucky enough to have a boat. It's the getting back part that sucks