16 categories

The oldest of everything still running.

One winner per category. The thing that has been up longest and is still up today.

1. Oldest social network: LiveJournal 12 social networks · since 1999 27y 200d
2. Oldest developer tool: curl 12 developer tools · since 1997 28y 355d
3. Oldest messaging app: ICQ 8 messaging apps · since 1996 29y 351d
4. Oldest text editor: Emacs 6 text editors · since 1976 50y 245d
5. Oldest programming language: Bash 5 programming languages · since 1989 37y 146d
6. Oldest commerce site: Amazon 4 commerce sites · since 1994 32y 119d
7. Oldest web host: Apache HTTP Server 4 web hosts · since 1995 30y 335d
8. Oldest cloud platform: AWS 4 cloud platforms · since 2006 20y 232d
9. Oldest project management tool: Jira 4 project management tools · since 2002 24y 203d
10. Oldest internet protocol: Email 4 internet protocols · since 1971 55y 31d
11. Oldest publishing tool: Mailchimp 4 publishing tools · since 2001 25y 304d
12. Oldest database: PostgreSQL 4 databases · since 1996 30y 116d
13. Oldest security tool: 1Password 3 security tools · since 2006 20y 167d
14. Oldest design tool: Photoshop 3 design tools · since 1990 36y 255d
15. Oldest search engine: Yahoo 3 search engines · since 1994 32y 244d
16. Oldest notes app: Evernote 3 notes apps · since 2008 18y 130d

Only categories with at least three entries get a page. Dates are founding dates from the written entries, not Product Hunt listing dates.