SNICK for those who don't recall, was the Saturday night block on Nickelodeon spanning from 1992-2004. It was a key component in what I would otherwise consider to be the "glory days"/golden age of Nickelodeon.
SNICK went hand and hand with TGIF on ABC (both were essentially, weekend appointment TV if you were a kid growing up in the '90s).
SNICK had shows such as (but not limited to) "Clarissa Explains it All", "Roundhouse", "Ren & Stimpy", "Are You Afraid of the Dark", "The Secret World of Alex Mack", "All That", "Space Cases", "The 100 Deeds of Eddie McDowd", "KaBlam!", "The Journey of Allen Strange", "Kenan & Kel", "The Mystery Files of Shelby Woo", etc.
To me, SNICK started to go downhill when they got rid of the big orange couch (which around June of 1999). Believe it or not, the orange couch was the heart and soul of SNICK (and helped create SNICK's identity in the first place).
Another thing that hurt the block in my estimation was when Nickelodeon started to drift away from the formula (besides the couch getting tossed aside). SNICK worked best when the block was made up of one live-action sitcom (e.g. "Clarissia..." and "Kenan & Kel"), one Nicktoon (e.g. "Ren & Stimpy" and "Rugrats"), one musical-comedy-variety show (e.g. "Roundhouse" and "All That"), and one wild card show (e.g. "Alex Mack", Space Cases", "Allen Strange", "Eddie McDowd", etc.).
Things were only made worst, when Nickelodeon tried to take SNICK into a completely different direction, with the "SNICK House" concept (with Nick Cannon as the host). It seemed like Nickelodeon was trying to copy what MTV was doing at the time with "Total Request Live". What people seemed to forget was that the shows themselves are what made SNICK not celebrity guests or music videos.
By the time that the SNICK House had run its course around the summer of 2001, it seemed apparent that Nickelodeon wasn't really trying anymore. There were basically, throwing shows around at random, with the SNICK name attached. At this point, they were using "elevator music" in the background with still photos and "talking bubbles" of the various SNICK stars.
By the fall of 2002, SNICK introduced a segment called "The On Air Dare", in which the cast of "All That" would perform acts that resembled does seen on "Fear Factor". Once again (as with the case with the SNICK House), Nickelodeon seemed to be throwing stuff in the air to see if they would stick (instead of simply following the tried and true formula and essence of SNICK in the past).
By the fall of 2004, Nick got rid of SNICK completely in favor of a second night of their TEENick block (which with in itself, resembles the SNICK House concept). The problem that I have with TEENick (not just because, the purist in me wishes that Nickelodeon had kept a hold of the SNICK brand) is that a lot of the shows on their schedule are already overexposed (like "iCarly" and "Drake & Josh" for example). Nickelodeon's programming has become awfully homogenized by this time (virtually every note worthy live-action show has to be a tween-oritened sitcom, like those on the Disney Channel at the moment).