Is there any rss app out there for iPhone, mac, or pc that scours tons of feeds on sites all over for a specific topic or keyword combination, and if one is listed now or a month from now it lets you know?

For example, I put in "Star Wars 15" and if any topics have those words in it now or a year from now...it shoots the feed to me.

Seems like there are no auto scour/searchable rss apps.