What is the difference between Poloniex and Coinbase?

Could you elaborate on the key differences between Poloniex and Coinbase? As both platforms operate in the cryptocurrency sphere, I'm curious to understand the nuances that set them apart. For instance, how do their services, user interfaces, coin listings, security measures, and fees compare? Additionally, are there any specific advantages or disadvantages of using either platform for buying, selling, or trading cryptocurrencies? Understanding these distinctions would help me make an informed decision about which platform to utilize for my crypto needs.