Feedsweep offers online configuration of widgets for any RSS feed, or combination of RSS feeds. I first discovered Feedsweep via the Mad Money Options site -- there, sitting on the front page is a Feedsweep widget carrying links to Jim Cramer's latest stock picks.
The Feedsweep site is here.
What could you do with fully configurable Feedsweep widgets? Well, you could use this for any stock market blog or aggregator that has RSS feeds. Yahoo Finance and Seeking Alpha, for example, have RSS feeds for every single stock ticker, so you could program this widget with your entire portfolio and get news headlines on it.
Here's a Feedsweep widget showing headlines from a stock portfolio. This took about three minutes to set up. But note the problem: if the same headline appears for more than one stock, the widget shows the headline twice since it simply aggregates RSS feeds without identifying the overlap between them.