check the alexia rankings, they tell the tale of the largely non technical audience.

the non-techies have gone to digg.

I still find reddit useful and interesting, mainly because the links all go back to the main stories.

Slashdot, inflammitory headlines/summaries, excellent community, excellent posts.

Digg exicitory headlines, horrible community, horrible posts

reddit typically accurate headlines, multiple submissions of similar stories(++ in my opinion), no comments in general

The higest impact will always probably be digg, as it is the lowest-common-denominator of the interet. Nothing wrong with that, however it has a definite audience.

Some of it is due to saturation and I get away with it because the project is not-for-profit and steam-punk, but a lot the Slashdot regulars have seen the SHPEGS information before.

The other thing is the posting of the details of the Microsoft patent infringement claims today. Slashdot is still very open source/anti-Microsoft and although there is geek interest in renewables, it's an IT crowd with a lot of personal and business investment in open source software.

Looks like Prof Goose has added the Ghawar story to Slashdot. Visit the firehose and up vote it and we'll see if it gets posted.

Digg and Reddit appear to be blackballing theoildrum.com for the moment. I'd guess the small scope of the usual posters and the poor submission to acceptance ratio.