I wish I could get something more out of this than "Quora has a lot of interconnected Topics". I've never used Gephi but it seems like there are at least small ways to start making network diagrams like that more readable.

This visualization of the Marvel social graph does things like coloring bundles, and surfacing larger node names at higher zoom levels: http://exposedata.com/marvel/data1/

Would have liked to have seen some sort of indicator of gross subject---tech this way pop-culture this way etc. Don't know if the data lends itself to an axial arrangement, but if so, that would be useful. Interesting none the less...

Much cool in this sector. Quora is doing a great job helping to realize the dream of the semantic web.

By the time I looked at it, it was very very slow, and nearly killed firefox. Love the concept though.

Where is the ontology available for download?

If you scraped it, do you mind sharing the scraper and the data?