The simplest explanation for what the difference between Syndicated episodes and the originals is that in most cases, the episodes are edited down from their original version so that there is more time to run commercials during a syndication airing. The amount of footage removed usually runs, I'd say, anywhere from 30 seconds to a minute. Also, the commercial breaks often occur in different places than the original broadcast versions. Sometimes, time compression is used to shorten the run-time of an episode, this is where, I believe, the footage is slighly sped up.
To elaborate, the main contributing factor to the need to cut the shows is that most syndication takes place on a "barter" system, wherein the distributor lets local stations have a show for very little money in exchange for the fact that there will already be some commercials placed on the tape/satellite feed sent to them. That's where the distributor makes a good portion of its money--selling national ads on syndicated programming. Of course, they still need to leave ad time for the local TV station to make their money, thus the show has to be shortened.
Yes, before Brad P chimed in, I was going to say that 30 to 60 seconds edited out of an episode is a pretty minor syndicated cut, which generally means the show is newer.
Nowadays, sitcoms are made to last about 22 minutes and allow 8 minutes for commercials. Some of the shows from the 80s and earlier would probably actually have been made to last about 25 to 26 minutes, allow only 4 to 5 minutes for commercials. So when networks air those old shows today, they've got 3 minutes to shave off to allow for commercials (to get their 8 minutes of ads in every half hour).
So essentially, I'm used to syndication cuts of the 3-minute variety as opposed to the 30- or 60-second types. But on DVD, I'm not used to them at all because Homie don't play that!
And often the show opening title sequence is shortened in syndication, meaning that much less need be removed from the show itself, which of course is a good thing.
Some of the older shows from the 60's and 70's have, on average. 5-7 min's of cut footage. An example of this is in the "bionic" series, 6M$M and Bionic Woman series. The syndicated versions that have aired on the SciFi Channel in the past have between 5-7 minutes removed as compared to the originally-aired version.
Yeah, I think those were hour-long shows, right? One-hour dramas suffer from about double the amount of time cut for syndication as sitcoms.
I can't even watch The Twilight Zone on TV anymore (the half hour or hour-long shows); it drives me crazy. I know the episodes so well in their uncut form that I just can't stand the cuts.
It really depends on when the episodes were originally made, as compared to when the syndicated cuts were produced. Generally, the longer the time in between, the more time is cut.
Shows from the Seventies were generally over 50 minutes for a one hour program. Most networks are now running one hour shows which run about 44 - 45 minutes. 10% or more of the program gets cut out in order to fit a program into today's advertising model.
In my mind, even a few seconds cut is too much. In most cases, syndicated cuts are missing MINUTES, not SECONDS of content. And usually there is no reason to revert to the cut episodes on a DVD release. It seems to be (most often) sloppiness on the part of the studios or DVD producers - since we can be almost certain that there are still complete editions available of most shows from the last 20 years.