# Concept catalog **URL:** https://forum.essenceofsoftware.com/c/concept-catalog/5.md [Latest](https://forum.essenceofsoftware.com/latest.md) · [Categories](https://forum.essenceofsoftware.com/categories.md) · [Tags](https://forum.essenceofsoftware.com/tags.md) --- ## [About the Concept catalog category](https://forum.essenceofsoftware.com/t/about-the-concept-catalog-category/28)
**Author:** [@dnj](https://forum.essenceofsoftware.com/u/dnj)\ **Replies:** 1\ **Last updated:** [November 17, 2021, 4:36pm UTC](https://forum.essenceofsoftware.com/t/about-the-concept-catalog-category/28 "2021-11-17T16:36:21Z")
Here’s a place for us to collaboratively construct a catalog of concepts. Feel free to propose a concept, new or old, and to comment on previous proposals. See Upvote topic for an example of what a catalog entry might lo… --- ## [Different kinds of authentication](https://forum.essenceofsoftware.com/t/different-kinds-of-authentication/319)
**Author:** [@xlawin](https://forum.essenceofsoftware.com/u/xlawin)\ **Replies:** 1\ **Last updated:** [September 8, 2026, 3:30am UTC](https://forum.essenceofsoftware.com/t/different-kinds-of-authentication/319 "2026-09-08T03:30:31Z")
Authentication can be implemented in various ways, such as passwords, SMS verification codes, and biometrics. Should these be modeled as separate concepts, or as different implementations of a single, unified Authenticat… --- ## [One input stream, three shapes of the past — is branching undo a freestanding concept?](https://forum.essenceofsoftware.com/t/one-input-stream-three-shapes-of-the-past-is-branching-undo-a-freestanding-concept/308)
**Author:** [@Scott](https://forum.essenceofsoftware.com/u/Scott)\ **Replies:** 0\ **Last updated:** [July 10, 2026, 3:21pm UTC](https://forum.essenceofsoftware.com/t/one-input-stream-three-shapes-of-the-past-is-branching-undo-a-freestanding-concept/308 "2026-07-10T15:21:59Z")
Following up on the concept-boundary conversations: we built a small interactive exhibit arguing that “undo” is three concepts, not one concept with options — Undoing Undos. Same input stream, three engines, each keeping… --- ## [Is there a Design Concept Zoo?](https://forum.essenceofsoftware.com/t/is-there-a-design-concept-zoo/26)
**Author:** [@spdegabrielle](https://forum.essenceofsoftware.com/u/spdegabrielle)\ **Replies:** 4\ **Last updated:** [June 25, 2026, 6:40pm UTC](https://forum.essenceofsoftware.com/t/is-there-a-design-concept-zoo/26 "2026-06-25T18:40:16Z")
Continuing the discussion from How do concepts change?: @dnj mentioned that it was desirable to avoid creating a new name for small variations. Should there be a Design Concepts Zoo like https://quantumalgorithmzoo.org … --- ## [Alloy caught what we missed!](https://forum.essenceofsoftware.com/t/alloy-caught-what-we-missed/298)
**Author:** [@Scott](https://forum.essenceofsoftware.com/u/Scott)\ **Replies:** 9\ **Last updated:** [June 12, 2026, 9:44pm UTC](https://forum.essenceofsoftware.com/t/alloy-caught-what-we-missed/298 "2026-06-12T21:44:13Z")
We’ve been building Grace Commons GitHub - scottromack/grace-commons: Atomic patterns (concepts) and applications, expressed as structured natural language. Code is derived; intent is canonical. · GitHub — a library of… --- ## [A new attempt at a catalog of software concepts, using Alloy](https://forum.essenceofsoftware.com/t/a-new-attempt-at-a-catalog-of-software-concepts-using-alloy/216)
**Author:** [@dpapathanasiou](https://forum.essenceofsoftware.com/u/dpapathanasiou)\ **Replies:** 1\ **Last updated:** [May 18, 2026, 11:56am UTC](https://forum.essenceofsoftware.com/t/a-new-attempt-at-a-catalog-of-software-concepts-using-alloy/216 "2026-05-18T11:56:44Z")
Hi all, I was quite taken by the book’s idea of creating a catalog of concepts from which applications could be composed more efficiently than designing and building from scratch. Here’s my own attempt at getting start… --- ## [Zoom's Missing Concept](https://forum.essenceofsoftware.com/t/zooms-missing-concept/293)
**Author:** [@suryakasturi](https://forum.essenceofsoftware.com/u/suryakasturi)\ **Replies:** 1\ **Last updated:** [February 13, 2026, 2:29pm UTC](https://forum.essenceofsoftware.com/t/zooms-missing-concept/293 "2026-02-13T14:29:24Z")
I am writing on the Zoom’s Missing Concept case study. I think the case study is directionally right but inaccurate in how it arrived at those conclusions. The concept of starting a meeting, sharing that link, and al… --- ## [Reviewing Prototype eCommerce Concept Catalog](https://forum.essenceofsoftware.com/t/reviewing-prototype-ecommerce-concept-catalog/165)
**Author:** [@evan](https://forum.essenceofsoftware.com/u/evan)\ **Replies:** 1\ **Last updated:** [April 7, 2023, 1:19pm UTC](https://forum.essenceofsoftware.com/t/reviewing-prototype-ecommerce-concept-catalog/165 "2023-04-07T13:19:03Z")
tl;dr: check out the prototype Concept Catalog, designed to help designers develop applications and share knowledge. Leave feedback / thoughts in this thread! Links: Full Concept Catalog, Shopping Cart Concept, Catalog … --- ## ["Order" as an app](https://forum.essenceofsoftware.com/t/order-as-an-app/88)
**Author:** [@Henri](https://forum.essenceofsoftware.com/u/Henri)\ **Replies:** 5\ **Last updated:** [January 21, 2022, 8:54pm UTC](https://forum.essenceofsoftware.com/t/order-as-an-app/88 "2022-01-21T20:54:57Z")
Hello Is an “order” a concept or an app? I quote Daniel’s thoughts on an email stream, in order to port the discussion to this forum: " I’ve been pondering exactly this example (but thinking about Amazon and how I’d de… --- ## [Comments, Notes and Tags](https://forum.essenceofsoftware.com/t/comments-notes-and-tags/82)
**Author:** [@pwilczynski](https://forum.essenceofsoftware.com/u/pwilczynski)\ **Replies:** 13\ **Last updated:** [January 11, 2022, 12:35am UTC](https://forum.essenceofsoftware.com/t/comments-notes-and-tags/82 "2022-01-11T00:35:24Z")
Over the past decade, we’ve evolved a number of overlapping / redundant concepts, all of which are related to a central concept, which I’ll call a highlight, which roughly corresponds to what the W3C Annotation Data Mode… --- ## [What is a "like"?](https://forum.essenceofsoftware.com/t/what-is-a-like/66)
**Author:** [@dmax](https://forum.essenceofsoftware.com/u/dmax)\ **Replies:** 2\ **Last updated:** [December 24, 2021, 1:46pm UTC](https://forum.essenceofsoftware.com/t/what-is-a-like/66 "2021-12-24T13:46:58Z")
I was trying to think through the question of, “What is a ‘like’?” in the context of LinkedIn. I was having difficulty thinking of it as a concept because when a member likes something, it means a bunch of things, such a… --- ## [Comparing similar concepts across products](https://forum.essenceofsoftware.com/t/comparing-similar-concepts-across-products/64)
**Author:** [@dmax](https://forum.essenceofsoftware.com/u/dmax)\ **Replies:** 1\ **Last updated:** [December 21, 2021, 8:11pm UTC](https://forum.essenceofsoftware.com/t/comparing-similar-concepts-across-products/64 "2021-12-21T20:11:17Z")
When you compare the behavior similar concepts across different products, like “sharing a folder” on Dropbox vs Google Drive, I think that there’s value in highlighting the differences both as an inducement to the compan… --- ## [Concept Ideas: Presence (of a user on a system) - example Concept Idea](https://forum.essenceofsoftware.com/t/concept-ideas-presence-of-a-user-on-a-system-example-concept-idea/50)
**Author:** [@kimmeyh](https://forum.essenceofsoftware.com/u/kimmeyh)\ **Replies:** 0\ **Last updated:** [December 1, 2021, 6:23pm UTC](https://forum.essenceofsoftware.com/t/concept-ideas-presence-of-a-user-on-a-system-example-concept-idea/50 "2021-12-01T18:23:56Z")
Concept Ideas - not fully developed, but seem like they would be good ideas for concepts (or are already concepts in wide usage?). Forum participants can then fully develop the Concept and post. Presence: Used in Slac… --- ## [Favorite(media): in which a user saves item for later review](https://forum.essenceofsoftware.com/t/favorite-media-in-which-a-user-saves-item-for-later-review/30)
**Author:** [@spdegabrielle](https://forum.essenceofsoftware.com/u/spdegabrielle)\ **Replies:** 4\ **Last updated:** [November 17, 2021, 4:53pm UTC](https://forum.essenceofsoftware.com/t/favorite-media-in-which-a-user-saves-item-for-later-review/30 "2021-11-17T16:53:02Z")
Favorite concept, in which a user saves item for their own review later. Mapping: UI element where a user saves a piece of media including a video, post, page, etc. Examples: Discourse as ‘bookmark’ and other forum web… --- ## [Wave: asynchronous content free message](https://forum.essenceofsoftware.com/t/wave-asynchronous-content-free-message/31)
**Author:** [@spdegabrielle](https://forum.essenceofsoftware.com/u/spdegabrielle)\ **Replies:** 2\ **Last updated:** [November 17, 2021, 4:27pm UTC](https://forum.essenceofsoftware.com/t/wave-asynchronous-content-free-message/31 "2021-11-17T16:27:33Z")
Wave: send a message to the receiver that only contains the senders identity - no content - the meaning is context dependent, may be influenced by ui(the change from poke to wave), or subverted by users. Mapping: UI ele… --- ## [Upvote: sample concept catalog entry](https://forum.essenceofsoftware.com/t/upvote-sample-concept-catalog-entry/32)
**Author:** [@dnj](https://forum.essenceofsoftware.com/u/dnj)\ **Replies:** 1\ **Last updated:** [November 17, 2021, 4:13pm UTC](https://forum.essenceofsoftware.com/t/upvote-sample-concept-catalog-entry/32 "2021-11-17T16:13:29Z")
Name: Upvote \[Item, User\] Purpose: Track relative popularity of items Also known as: Like Related concepts: Reaction (send emotional reaction to author of post) Recommendation (track user approvals for future recomm…