I feel like this is almost certainly a duplicate, but I couldn't find what it's a duplicate of.
Is there an RSS feed for updates (new answers, edits, comments, maybe even votes) on your "favorite" questions? If no, can we have one?
This is now possible. I have written a small application called Stack2RSS that does exactly that.
Here is how it works: given an API request, the app will convert it to an RSS feed. Since there happens to be an API method for retrieving a user's favorite questions, stack2rss can easily generate a feed for this.
An example that fetches Jeff Atwood's (user #1) favorite questions on StackOverflow:
http://stack2rss.stackexchange.com/stackoverflow/users/1/favorites?body=true
stackoverflow part can be replaced with something like programmers.stackexchange to access favs from that site.
There was an error processing this page.The API response did not contain an array. My question is here
I can see how (perhaps) individualized RSS feeds are a bit much. Another solution to the problem is to have the same top-of-the-screen bar that notifies us of other activity can notify us of activity against our favorites.