No doubt, you have noticed the annoying spelling variations of the word "eCommerce".
There are many.
1) ecommerce 2) e-commerce 3) ECommerce 4) eCommerce 5) Ecommerce 6) any other variation you can think of....
Likely there are many more. I propose that until such time as convention (in your native tongue) settles on one variant over another, go with what you like. I like "eCommerce", and use it throughout this blog... for... ah... consistency. :)
No telling which variant will eventually win out as the dynamics of language progress over time. What's your vote? Let us know if you have a favorite.