Here are the core activities of the companies:
1. Offertomat: An online platform for purchasing services.
2. B2B Digitalfabrik: A digital factory for companies that implements complex IT projects.
3. TRIBUS Business GmbH: Development of IT platforms.
4. aico AG: Development of AI-supported software for automation and gamification.
5. tpm solutions AG: A network of experts for digital solutions, offering customers anonymized projects.
Please note that the descriptions are based on the provided information and may not be complete or up-to-date.