an old american tv programme used to start with a summary of what had
gone on before, then the commentator would say, 'confused? you will
be!"
What was it?

Hi Lina60!

The program you recall is the 1977 TV Series called SOAP.

"Soap" [TV-Series 1977-1981] 
http://www.imdb.com/title/tt0075584/maindetails


Memorable Quotes from  "Soap" 
 
"[after describing the often confusing plot line from the previous
epsiode at the top of every show]
Announcer: Confused? You won't be after this episode of "Soap" 

IMDB
http://www.imdb.com/title/tt0075584/quotes


"At the beginning of the show, off camera announcer Rod Roddy would
give a brief description of the convoluted storyline and then he would
conclude it with the line, "Confused? You won't be, after this episode
of...Soap". At the end of the show, he would ask a series of
life-or-death questions in a deliberately dead pan way - "Will Jessica
discover Chester's affair...?" This would be concluded with - "These
questions - and many others - will be answered in the next episode of
Soap."
Wikipedia
http://en.wikipedia.org/wiki/Soap_(sitcom)




Plot Summary

"Soap, a parody of soap operas, is a show about two sisters, Jessica
Tate and Mary Campbell and their families. The two families have all
sorts of problems such as: Sarcastic butlers, a war hero who's still
living in 1940's wartime and Mary's 2nd husband who once thought he
could make himself invisible and was abducted aliens, just to name a
few."
http://www.imdb.com/title/tt0075584/plotsummary


Search terms:
SOAP confused 


I hope this is helpful!

Best regards, 
Bobbie7

aye was beaten to this one..  SOAP :D

however Brasseye also used it on their newsroom sketches.. 
and hitchikers used it a couple of times..