Initially diet drinks often replaced sugar with artificial sweeteners called cyclamates and sometimes mixed with saccharin. The sweetness of cyclamates were discovered by accident in 1937 who apparently did not mind smoking in the lab since it was there that he was working on creating an anti-fever medicine when he tasted a sweetness after picking up his cigarette. In 1966 a study found that cyclamates were linked to cancer and in 1969 it was banned by the FDA. After the ban on the use of cyclamates diet drink makers, including Coca-Cola, turned to saccharin (also known as Sweet 'N Low) as a replacement artificial sweetener but this often lead to a chemical or bitter taste. The FDA also wanted to ban saccharin in 1977 due to correlations in cancer research until further review could be completed. They were unable to ban saccharin but food using it had to carry a special warning label, which was later repealed in the 1990's. By that time nearly all diet drink makers had already been using another artificial sweetener called aspartame (also known as NutraSweet). Diet Coke which was released in 1982 uses aspartame as a sweetener which is what leads to it's distinctively different taste from Coca-Cola Classic.
The first diet soda drink was a giner-ale called "No-cal" sold by Kirsch Bottling Company of Brooklyn, New York in 1952 and was originally made for diabetics. In 1958, Royal Crown Cola came out with Diet Rite. By the 1960's so-called "diet" products were increasing in popularity and Coca-Cola entered the diet soda market with Tab in 1963.
The name Tab has also offered some debate, but when Tab was created the Coca-Cola company had rejected the idea of calling it Diet Coke but agreed that it should have a short name. Coca-Cola used an early IBM computer to churn out a list of words no longer than 4-letters, but excluding any that were unpronounceable or too similar to other products. After paring this to a short list Tab was chosen as it was able to be used as a play on words - to keep "tabs" on your weight. The pink-hued packaging is likely a relic from it's creation in the marketing department's attempts to focus on weight-watching women customers.
When Tab was first introduced it too featured cyclamates and changed to saccharin when the FDA banned cyclamates. Tab still uses saccharin (mixed with aspartame) as a sweetener today but was overtaken by Diet Coke in the 1980's as Coca-Cola's major diet soda brand. At it's apex the Tab brand included Tab Lemon-Lime and Tab Orange. In the early 1990's when Pepsi released Crystal Pepsi, the short lived Tab Clear was sold but was pulled within a year. Tab has a dedicated fan following which keeps it going and is sold outside the US in Spain, South Africa, Lesotho, Namibia and Botswana. Recently a Tab energy drink was also released.
Most people today are familiar with Tab as a cola, but most remember it as a fad or relic from their past due to it being harder to find in some retail locations than others. My own grocery store carries it, but my mother, a Tab fan, goes to specific retailers to find it. I find that Tab has a distinctly chemical flavor to it which immediately reminds me that I'm drinking a diet soda. While the sweeteners may vary it is very similar to a Diet Pepsi flavor. The carbonation is rather average. I tend to steer clear of Tab because it gives me strong headaches between my eyes as though my blood vessels are squeezing tighter, making it harder for blood to move through, but this effect is not equal as some people drink it regularly.
Following, are two Tab caps currently in my collection...