Who is Coinbase?

As a cryptocurrency enthusiast, I'm curious to know more about Coinbase. Could you provide a brief description of who they are? Are they a leading player in the crypto exchange space? What services do they offer to their users? Are they a trusted and reliable platform for buying, selling, and trading digital currencies? I'd also be interested in knowing if they offer any additional features or tools to help users manage their portfolios or stay up-to-date with market trends. Thank you for any insights you can provide!