There’s one listed here. I would say Lemmy is still working on the “functionality” part, as it is missing many basic functions needed to meet what I think is the bare minimum. So it’s still very much only suitable for early adopters willing to put up with jankyness.

As with Maslow’s hierarchy it is essential for a design to meet the lowest need on the pyramid before progressing to meet further needs.

Functionality – for a design to meet any need it must work and it must meet the basic needs of the user. However, if this is all it does; it may well be seen as having little value if any to the user in the short to long-term.

Reliability – the next step is for your design to function in a reliable manner and present a consistent experience. This may increase the user’s perception of the value of your product from a purely functional one but it does not add large amounts of value either.

Usability – then a design should be simple to use and relatively forgiving of user error. When you meet this need the product is likely to be considered of middling value by the user.

Proficiency – a design which helps a user to do more or achieve more is one which is likely to be desired as a high-level of value and fulfil user needs more effectively.

Creativity – the final step in the design pyramid is to create products which fulfil all other needs and are beautiful not just in form but also in interaction and function. This is where the highest user value is placed (think Apple products for an example in real life).