What is an Initial Coin Offering (ICO)?

Could you please elaborate on what an Initial Coin Offering, commonly known as an ICO, actually is? I'm interested in understanding the core concept behind it, its purpose in the cryptocurrency ecosystem, and how it differs from traditional fundraising methods. Additionally, I'd like to know if ICOs are regulated and what kind of risks investors should be aware of when participating in one. Could you provide a brief overview of the ICO process, including the stages involved and any key considerations for potential investors? Thank you for your assistance.