Recently active topics in I want Sandy tagged with rss

(mostly posting this here to catalog it, i've already talked to Rael about it).

How about sending sandy a message along the lines of "follow <type> <data>", which Sandy could recognize as something to poll at regular intervals and email you updates on, such as:

follow ups 1Z4123455123 - This would be recognized as a UPS package tracking number, and polled every 6 hours or so via the RSS feeds at http://track2rss.sourceforge.net/ (same for dhl, fedex, usps)

follow flight XXXXX - Poll for the flight status on google's website and send you updates on gate information, delays, etc.

follow site www.slashdot.org - Visit the website (www.slashdot.org) and retrieve the RSS feed URL's, and poll it at regular times (I honestly wouldn't use sandy for this, bloglines is better, but for critical services like status.twitter.com or something it could be useful)

follow feed http://www.example.org/feed.rss - Follow this RSS feed directly, emailing you with updates

These could be extended with "special" tags like @weekly, @daily, @hourly, or @often to determine how often they should be polled (@often would be determined by Rael as the most frequent he's comfortable letting Sandy poll something).</data></type>

I click the link, go to Google reader; but the feed is blank.