I'm a bit late to write about this one, but I got an email from Daryl Willcox Publishing, the company behind Sourcewire, the other day. The company has gone from offering a just a set of pre-packaged RSS feeds for press releases to providing alongside a roll-your-own feed, similar to the one offered by Businesswire but not, unfortunately, PRNewswire.
One little twist to the custom feed idea that Sourcewire has added is the ability to use keywords to either filter the basic categories you have selected or pull in releases from other sectors you don't normally cover if those keywords pop up. The second option is potentially handy as it should come up with material from companies who you would normally not bother with, but who might on one occasion have something in my area that is worth covering. I'm not sure how useful this particular feature will prove to be in practice but it's worth a try.