This is a new one in the catalog -
Do a keyword search of the catalog - a sample screen is here.
You'll get back a result screen that looks a lot like this:
Note the result set - it has an RSS feed! Select it
and you'll get a mishmosh (that's RSS for you). Copy that URL into your favorite aggregator, and you'll see something like this:
Presto, you'll always be notified in your aggregator about new materials (or in some cases that I haven't quite figured out yet, changes in availability of materials already in the collection) for your favorite topic.
Some URLs if you are following along at home and want to just construct the RSS feeds directly:
http://www.aadl.org/cat/seek/search/X?knitting&searchscope=26&x=0&y=0&SORT=D&sourceid=Mozilla-search&rss=1 - Knitting RSS search feed