Number 73 provoked extreme reactions - I guess you either loved it or you hated it. I, for one, loved it, and was a regular viewer for most of its run.
It was disliked by many, simply because it was the show that replaced Tiswas, but as I'm slightly too young to remember Tiswas very well, this is the show that grabbed my attention on Saturday mornings. It was a very clever concept - a Saturday morning show set in a chaotic house full of larger-than-life characters - and it was very slick and well executed. Admittedly I was only eight years old at the time, but it was very easy to be taken in by it, and convince yourself it was all real.
The early seasons were the best - later on, things began to go downhill a bit as some of the cast left, and the winning formula was messed with. Unfortunately, the show was a victim of its own success. It was clearly much more complex to make than a traditional studio-based show, and required a large and very complex set. The production values were always high, and therefore expensive, and the show was forced to relocate, with the final season called "7T3" and set in a theme park. This was all a bit pants, but the early seasons were great - original and anarchic, and much better than the Beeb's offerings of the time.
I think it appealed because as well as all the usual guests, cartoons etc. from Saturday shows, it had a plot and a backstory, and the presenters were characters you could get to admire and follow. Dawn was always my favourite, she was hip 'n' trendy in an early-80s sort of a way, and was pretty nifty on a pair of rollerskates. In reality, Dawn was Andrea Arnold, who is now a film director of some repute. The show also launched the career of Neil Buchanan, who continues to present a lot of children's shows on ITV, especially art-based ones, and introduced Sandi Toksvig to a generation of kids.
What happened to the rest of them? Great, great stuff - I'll always remember The Sandwich Quiz, the bands in the basement, bizarre plot twists, and even stuff like the postal address and telephone number for the show (PO Box 73, Maidstone, Kent, ME15 6RS - "mee fifteen six ares" - and 0622 600000).