Senh: It's a good read on how to use Twitter to track news that you care about or market your brand. Lots of hashtags.
I'm just starting to submit stories from my blog to Digg, hoping against hope that they'll get some Digg love and drive some traffic back here. So far, no luck. The only Digg love my blog entries get is from me - and ONLY me. But I noticed a nice side effect - articles submitted to Digg almost instantly appear in Google's search results. Nice! Sure, the link goes to Digg, but from there, potential users can get here. It's a good trade-off.