the secret? hmm.. I guess what makes a good tagline/slogan is its catchyness
IMO it should carry details of activities and specialty of the company.
Marmite = Love it or Hate It - Because people either love ir hate it due to it's strong flavour
Intel = Intel inside - well known as quality so is a boast
M&M's - melts in your mouth not in your hands - denotes that people won't have a handful of melted chocolate in their hand
Coca Cola - It's the real thing - They are the original cola
Pepsi = The taste of a new generation - reply to Coca Cola
Visa - It's every where you want to be - how widely you can use it
Remington = I liked it so much I bought the Company - impressed by product so wanted it to sell
Nokia - Connecting people - the nature of mobile phones
Haig Whiskey = Don't be vague ask for Haig - EG don't ask for Scoth or Whiskey ask for their product
Greyhound = Leave the driving to us - speaks for it's as it's a bus company
Memorex = Is it live or is it Memorex - EG their video tape recorded in good quality
Tag lines are a catchy thing that relates to something about the product in general.
Last edited by MrFlicker; 7 April, 2010 at 19:15 PM. Reason: typo
Adidas has a similar one: "Impossible is Nothing" , can be read in reverse too.
I like this one from Citibank: "Citi Never Sleeps"
When you think of a new tagline be original and don't use words like "quality", "excellence" and "commitment". 'Everyone' is using those and people are blind to them like webmasters are blind to online ads.