Bulle Algorithm Challenge Rules

Version v1 of 29 April 2026. This page is not indexed by search engines. It is reachable only through the direct link from the Challenge page. The French version of these rules prevails in case of discrepancy.

Art. 1. Organiser

The Bulle Algorithm Challenge (the "Challenge") is organised by SHABON, the company publishing the Bulle application, headquartered in France. All correspondence regarding the Challenge shall be sent by email to contact@shabon.fr.

Art. 2. Purpose

The Challenge consists in proposing:

• a public evaluation metric objectively meeting the principles stated on the Challenge page (generalist, engagement-correlated, non-divisive, fair, hot information, anti-spam, temporal decay, second chance, transparent);
• a concrete algorithmic application for ranking publications according to that metric;
• the ranking CSV file produced by that algorithm applied to the provided dataset.

The selected proposal will be the subject of a deeper collaboration with its author towards an actual implementation into the platform.

Art. 3. Eligibility

The Challenge is open to any natural person of legal age and to any legal entity (company, non-profit, lab, educational institution) capable of expressing free and informed consent.

Participation is free, with no purchase obligation. Employees of SHABON and their close relatives may not compete.

Only one submission is accepted per participant or team. In case of multiple submissions, only the latest one received before the deadline is considered.

Art. 4. Schedule

The Challenge is open from the publication date of these rules and ends on June 1st, 2026 at 11:59 pm (Paris time). No submission received after this date will be evaluated.

Art. 5. Dataset access

The dataset is made available exclusively through the public Challenge page (/en/algorithm-challenge), after the participant has authenticated with a valid Bulle account and explicitly accepted these rules.

This restriction allows SHABON to keep traceability of dataset accesses and to limit abusive usage. Only people who legitimately obtained the dataset through this page will be able to submit their work for evaluation: any submission from a participant who did not download the dataset through the official channel will be rejected.

Art. 6. Participant commitments on the dataset

By downloading the dataset, the participant commits:

• to use the dataset strictly within the scope of the Challenge, and for no other commercial, scientific or personal purpose;
• to not redistribute the dataset to third parties, in whole or in part, in any form whatsoever (file, copy, mirror, public or private repository, cloud sharing, etc.);
• to not attempt to re-identify the creators or users represented in the data, by cross-referencing with external sources or any other method;
• to delete the dataset from all storage at the end of the Challenge, unless SHABON requests otherwise;
• to notify SHABON of any leak or accidental loss of control of the dataset within 72 hours.

Failure to comply with any of these commitments results in immediate disqualification from the Challenge and may give rise to legal action under intellectual property, personal data protection, or general law.

Art. 7. Submission format

A complete submission consists of the two following items, compressed into a .zip file:

• a description document of one A4 page maximum, in font size 12, presenting the proposed evaluation metric, the corresponding algorithm and the associated formulas;
• a submission.csv file containing the ranking produced by the algorithm, with three columns: date, publication_id, rank. One row per (date, publication_id) pair present in the dataset. Ranks start at 1, are unique within a date, and have no gaps.

The submission is sent to contact@shabon.fr with the subject "Bulle Algorithm Challenge". Source code is optional; if attached, it must be released under any open licence chosen by the participant.

Art. 8. Evaluation and selection

Submissions received are evaluated by SHABON on the basis of:

• the consistency between the proposed metric, the algorithm and the submitted ranking CSV;
• the compliance with the nine principles stated on the Challenge page;
• the simplicity, auditability and explainability of the method;
• the operational feasibility of an integration into Bulle.

SHABON reserves the right to discard any submission clearly non-compliant with these rules (incorrect format, unknown identifiers, dataset not legitimately downloaded, fraud or re-identification attempt).

Art. 9. Recognition

The selected proposal benefits from:

• a dedicated public article on Bulle's blog, presenting the method and its author, unless an explicit anonymity request is made;
• a deeper collaboration with the Bulle team towards the actual implementation of the algorithm into the platform;
• a public credit on Bulle's algorithm page if the solution is integrated into the platform.

No cash prize is associated with this Challenge.

Art. 10. Display of submissions

A dedicated page may be published after the deadline, to showcase the rankings actually submitted and display the publications proposed by the various algorithms for each evaluated day. Participants will be informed of the publication of this page, and may request to appear under a pseudonym or not to appear at all.

Art. 11. Intellectual property

The participant retains all intellectual property rights on the method, source code and any production associated with the submission.

By participating, the participant grants SHABON a non-exclusive, free and worldwide licence to: (i) evaluate the submission, (ii) publicly cite the participant's name and short description of the approach, (iii) technically evaluate the possibility of integrating the method into Bulle.

Any actual integration of the method into Bulle is subject to a separate written agreement between SHABON and the participant, specifying the scope of use and the public credit to the author.

Art. 12. Personal data

Personal data provided by the participant (name, email, Bulle identifier, dataset download traces) is processed by SHABON for the sole purpose of managing the Challenge, in compliance with the GDPR. It is not shared with any third party.

The participant has at all times a right of access, rectification, opposition and deletion on their data, exercisable by email at contact@shabon.fr.

Art. 13. Modification or cancellation

SHABON reserves the right to amend these rules, extend, postpone or cancel the Challenge in case of force majeure or any event beyond its control, without incurring any liability. Any substantial change is announced publicly on the Challenge page.

Art. 14. Acceptance of the rules

Participation in the Challenge implies full and unconditional acceptance of these rules. Acceptance is materialised at the time of dataset download. Any dispute over their interpretation or application is handled in good faith by SHABON, whose decisions are final.

Art. 15. Governing law and jurisdiction

These rules are governed by French law. Any dispute regarding their interpretation or execution falls under the exclusive jurisdiction of French courts, except where mandatory legal provisions provide otherwise.

For any question regarding these rules, write to contact@shabon.fr.