Youtube – How to save all the comments I’ve made on YouTube videos

Channels on YouTube have RSS feeds, so subscribe to all of your favourite channels' RSS feeds in Google Reader (or another online feed reader).

It seems not possible to do what you want. The blog cited in the other answer states search commands that don't work today (e.g., Apple, this week returns videos from 3 years ago).

There is an API reference showing how you could do it with GET, and there's an advanced search that also modifies the URL.

It's possible to do what you want, but not how you want to do it.