Remember when a Kit Kat was really a Kit Kat?

Remember the days when the only decision you had to make when buying a KitKat was whether to get the two-finger snack or go the whole hog on the four finger option. Now, not only is there chunky, chunky duo and king-sized chunky, Kit Kat has been one of the brands leading the way with alternatives to the traditional recipe.

Latest on the ‘caramel trail’ is Aero, which has topped its famous bubbly chocolate with caramel. This is all part of Nestlé’s plans to make a "huge" investment in Aero this year, kicking off with the re-introduction of Aero Caramel. The company is pouring £5m into a four-month media campaign to celebrate the relaunch of the Caramel variant, which was originally introduced in 2004.

The "irresistibubble" product is getting the full treatment from an integrated advertising campaign including interactive touchscreen quizzes at bus stops to its own Facebook page (we’re still not too sure why you’d befriend a chocolate bar on Facebook). Nestlé, which has also launched an Orange variant of its Aero block, recently reported that sales of Aero blocks soared during 2010, up 70% year on year.

This all follows on the back of perhaps the most bizarre – and to be honest slightly unsettling combination - Marmite’s pre-Christmas launch of a creamy milk chocolate bar with a hint of the famous yeasty spread. Unilever, owner of Marmite marketed the bar as a "devious treat for the in-laws" at Christmas or for those struggling to find a present for a loved one.

We love a bit of chocolate just like the next team, but we also have a nagging concern. If you play around too much with a much-loved institution like the good old Kit Kat or Aero, at what point do you begin to forget why you fell in love with it in the first place? At what point does Kit Kat stop being Kit Kat and start being something else that perhaps you don’t like as much? How far is too far and when do the manufacturers stop staying true to the brand they spent so many years building up?

Now, what would be interesting, perhaps Cadbury’s will really go radical with a re-launched Dairy Milk that has added……chocolate?