“What are examples of businesses which are marketplace ecommerce platforms?”
First, I had to look that up. Aren’t all e-commerce sites marketplaces?
According to Wikipedia, which is never wrong, "An online marketplace (or online e-commerce marketplace) is a type of e-commerce site where product or service information is provided by multiple third parties, whereas transactions are processed by the marketplace operator. "
Vertical - Sells from many different sources, but focuses on one type of product. e.g. TrueFact.com (jewelry)
Horizontal - Many types of products, with a shared characteristic. e.g. Pango.com is a stie for “enthusiasts.” that is, pick your area (Camping, Golf, Photography) and you are taken to a specific area for that type of product.
Global - Sells everything. The obvious choices are eBay and amazon. I’ll hold off on finding less obvious choices in case anyone else wants to post them.
Our local gigant is Allegro.pl
Interestingly, Naspers (which owned Allegro group) connected it to OLX.pl (a free, ad-fueled marketplace), which is big in Poland as well. These two, along with Ceneo (very popular price comparison platform), one of the biggest the house marketplace and car marketplace - all of them which Allegro owns - constitutes quite a monolopy. And allegro itself reaches to ~60% of Polish internet users.
It took me a bit to go through the info but look - there’s a valuable context here as well! ^^