Expand IKEA known instance in InnerSource Hackathon pattern

Add details sourced from Shanmugapriya Manoharan's December 2024
InnerSource Commons community call talk: virtual one-day format,
two participation categories, maintainer pre-work, judging panel,
and outcomes (6 countries, ~6 projects, ~50% landscape growth,
one open-sourcing candidate). Also add Shanmugapriya to Acknowledgments.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

Author: rrrutledge

patterns/2-structured/innersource-hackathon.md

@@ -103,7 +103,12 @@ All these help scale InnerSource in the organization.
 
 ## Known Instances
 
-* **IKEA** (Ingka Group)
+* **IKEA** (Ingka Group) organized a company-wide InnerSource hackathon to scale InnerSource adoption beyond the early adopters already familiar with open source practices. Despite leadership support, IKEA struggled to spread InnerSource awareness to engineers new to collaborative ways of working and to attract contributions to existing InnerSource projects. The event was organized and run by Ingka Group's Open Source Program Office (OSPO), which also supports InnerSource adoption across the engineering organization.
+
+  The hackathon was held as a virtual, one-day event open to all developers in the company, with a few extra days allowed for participants to finish and submit their work. Participants could join individually or in teams and chose from two categories: (1) **start a new InnerSource project** — either from scratch with documentation in place from the beginning, or by converting an existing project to follow InnerSource guidelines and publishing it in the company's InnerSource marketplace; or (2) **contribute to an existing InnerSource project** — before the event, project maintainers pre-listed features and issues tagged as "hackathon" or "good first issue" so participants could pick them up on the day. The judging panel comprised representatives from different business areas across the company, all strong advocates of InnerSource.
+
+  The event drew participation from engineers across **six countries** and resulted in contributions to around **six InnerSource projects**. The InnerSource project landscape grew by approximately **50%** as a result of the event. One newly created project was identified as a strong candidate for open sourcing. Notably, the hackathon reached many developers who would not have engaged with InnerSource through conventional awareness campaigns — making it especially effective for the late majority who had previously ignored the topic. Shanmugapriya Manoharan (Engineering Advisor, OSPO, IKEA IT AB) shared this experience at an InnerSource Commons community call in December 2024. See: [Hackathon: A Fun and safe approach to get started with InnerSource](https://youtu.be/7RWJUKanbqQ) (InnerSource Commons Community Call, December 2024).
+
 * **The Aerospace Corporation** organized an internal InnerSource contribution festival inspired by open source contribution festivals at conferences like KubeCon/CloudNativeCon. Aerospace is a Federally Funded Research and Development Center (FFRDC) where developers charge time to government contracts, making InnerSource adoption especially challenging because work not embedded in funded tasking does not happen. The event was organized by a software best practices team and held as a hybrid event (virtual and in-person in El Segundo, California). They secured dedicated funding so that all 31 participants across 21 departments could charge their time to the event. Tasks were prepared with project maintainers, documented with clear definitions of done and impact statements, and organized on task boards. At least one maintainer from every participating project was available for Q&A throughout the day. During and shortly after the event, 15 tickets were closed. Notably, one developer used the event to contribute a feature he needed back to an internal library rather than forking it — a direct demonstration of InnerSource solving the "fork storm" problem the company had been experiencing. Two-thirds of participants had never heard of InnerSource before the event, yet 100% of survey respondents agreed that InnerSource would have a positive impact on development and wanted to participate in a future event. Traffic to the company's internal documentation site nearly doubled in the month following the event. See: [Kickstarting InnerSource with a Contribfest](https://www.youtube.com/watch?v=J5KeCHFbnWA) (InnerSource Commons Summit 2025 talk by Trin Baumgarten and Caroline T Jones).
 
 ## Status
@@ -116,4 +121,5 @@ All these help scale InnerSource in the organization.
 
 ## Acknowledgments
 
+* Shanmugapriya Manoharan (IKEA IT AB) for [sharing IKEA's hackathon experience](https://youtu.be/7RWJUKanbqQ) at an InnerSource Commons Community Call, December 2024.
 * Trin Baumgarten and Caroline T Jones (The Aerospace Corporation) for [sharing their experience](https://www.youtube.com/watch?v=J5KeCHFbnWA) at the InnerSource Commons Summit.