What is the best platform or tool to build a service design portfolio on? (Example: medium, WordPress, Behance, etc?)

My two cents

Any: tools don’t matter that much to building your portfolio. I would just pick one that you are already comfortable with or is easy to use (see my favourites and the AI answer)
Always have an “archive” on a platform you own or pay for: services and tools disappear on the internet with time. So it might make sense to invest a bit of money to have a place you own (or pay for) as a backup in case the free social media platform you choose closes.
My personal favourite: Squarespace and podia are two pretty simple tools I like to use to build websites. Squarespace has awesome templates and Podia is a great choice if later you want to build a community and share your expertise in courses, webinars, etc. If you are a bit nerdy, WordPress can be a great choice (even if, personally, I never got to like it myself as I feel I spend too much time setting up things and less time creating my content.

I've asked this same question to the ChatGPT generative AI. Here is the unedited answer it gave me. Take it with a grain of salt.

There are many platforms that can be used to build a service design portfolio. Some popular options include:

Behance: Behance is a platform specifically designed for creative professionals to showcase their work. It’s a great option for service designers looking to build an online portfolio.
WordPress: WordPress is a flexible platform that can be used to build a wide range of websites, including portfolios. It’s user-friendly and has a large number of themes and plugins to help you create a professional-looking portfolio.
Medium: Medium is a blogging platform that can be used to showcase your writing and design work. It’s a good option for service designers who want to share their work and ideas with a wider audience.
Squarespace: Squarespace is a website builder that offers a range of templates specifically designed for portfolios. It’s a good option for service designers who want an easy way to create a professional-looking online portfolio. Ultimately, the best platform for your service design portfolio will depend on your specific needs and preferences. Consider factors such as the type of work you want to showcase, the level of customization you need, and your budget when choosing a platform.