"Is of Identy" in Pop Media

Below are some examples of famous advertisement slogans:
"Coke is it." (Coca-Cola)
"A diamond is foreever." (De Beers Consolidated)
"Guinness is good for you." (Guinness)
"Plop, plop, fizz, fizz, oh what a relief it is." (Alka Seltzer)
"Don't be vague. Ask for Haig." (Haig Scotch)
"It is. Are you?" (The Independent)
"You don't have to be Jewish to love Levy's." (Levy's Rye Bread)
"The future's bright. The future's Orange." (Orange)
"Where's the beef?" (Wendy's)
And here gives some other examples that work better without E-prime (but what in the world do they mean?):
"I yam what I am and that's all what I yam." (Popeye the sailor man)
"And God said unto Moses, I AM THAT I AM...." (God in Exodus 3:14)
"The Truth is from thy Lord; so be not at all in doubt." (English translation of the Koran, 2.147)
"How are you?" (common greeting)
"You are my sunshine, my only sunshine." (folk song by Jimmie Davis)
"Will you be my Valentine?" (Valentine saying)
"Is that all there is?" (Song sung by Peggy Lee)