# Marc Andreessen

> 1971– · Entrepreneur, Creator of Mosaic/Netscape
>
> **Recorded contribution:** Mosaic browser; Netscape; Andreessen Horowitz; "software is eating the world"

## How to use this dossier

Read for a causal chain, not a hero story: inherited problem → contribution → mechanism → downstream capability → limit. Then close the page and complete the reconstruction exercise from memory.

## 1. Historical orientation

As a University of Illinois student and NCSA employee, Marc Andreessen worked with Eric Bina and a broader team on NCSA Mosaic, released in 1993. Mosaic helped make the Web accessible through a graphical, cross-platform browser. Andreessen then co-founded Netscape, whose browser and commercial strategy accelerated Web adoption, and later became a venture investor. His role joins interface design, product distribution, and institution-building rather than a single solitary invention.

## 2. The problem inherited

The early Web worked, but using it demanded unfamiliar tools and lacked the polished graphical integration and distribution needed for a mass audience.

## 3. The central contribution

Andreessen co-developed Mosaic and co-founded Netscape, helping turn open Web protocols into an accessible graphical medium and a major software platform contest.

## 4. Reconstruct the mechanism

1. Resolve a URL and request a resource over an open network protocol.
2. Parse returned hypertext into a navigable document structure.
3. Render text and images in one graphical window with clickable links and history.
4. Package the client across common desktop systems and distribute it to a growing public.

## 5. What changed downstream

- Graphical browsing broadened who could use the Web and stimulated site creation and online commerce.
- Netscape's rise helped make browsers a strategic platform and shaped later standards and antitrust conflicts.

## 6. Attribution, limits, and uncertainty

- Mosaic was produced by a team and inherited essential work from Tim Berners-Lee, browser predecessors, Internet standards, and NCSA infrastructure.
- Later investing claims such as 'software is eating the world' are arguments, not technical laws, and should be evaluated against labor, hardware, regulation, and market power.

## 7. Reconstruction lab

Build a tiny browser that fetches local HTML, renders headings, text, one image, and links. Record which Web capabilities come from protocols, which from the browser, and which from the operating system. Add a page containing malformed markup and an unsupported media type, then define graceful failure before implementing it. Compare Mosaic-era documents with a modern page that depends on scripts, fonts, storage, and remote APIs. Draw the growth in the browser’s trusted computing base. The result should make clear that accessibility came not from graphics alone, but from composing open addressing, retrieval, parsing, rendering, navigation, and portable distribution.

## 8. Evidence trail

- [NCSA Mosaic](https://www.ncsa.illinois.edu/research/project-highlights/ncsa-mosaic/) — National Center for Supercomputing Applications
- [Marc Andreessen](https://www.britannica.com/biography/Marc-Andreessen) — Encyclopaedia Britannica
- [Why Software Is Eating the World](https://a16z.com/why-software-is-eating-the-world/) — The Wall Street Journal

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*Research checked 2026-08-09. Dates, roles, and claims about living people are historical snapshots. Linked sources remain the authority; this dossier is original instructional synthesis.*