Subscribe to an Etsy search by RSS.
Run a search on Etsy, then replace www.etsy.com with etsy.nyh.name in the URL. That's your RSS feed.
So if you searched for "octopus" in vintage, you would change http://www.etsy.com/search/vintage?q=octopus to http://etsy.nyh.name/search/vintage?q=octopus.
This bookmarklet changes the URL for you:
This bookmarklet gives you a URL to copy and paste in a RSS reader app:
You can bookmark either (perhaps in the bookmarks bar of your browser), then click that bookmark when you're in an Etsy search.
Do you want feeds for a shop or someone's public favorites? Etsy has those already.
By Henrik Nyh. View source.