There have been a few new cool web services announced recently. Bloglines, a great web-based RSS aggregator, now offers package tracking. Using a USPS, UPS, or FedEx tracking number, you can now "subscribe" to a particular shipment and keep track of it as it progresses.
Google continues to dominate with the addition of stock quote lookups - just enter a ticker symbol and get a quote, chart, and other data. Google now also works with Firefox's prefetch feature to load your search results more quickly. If your 1st search result is highly relevant as determined by Google, the search results page will load the first result in the background, making load time appear faster.