Somehow when I spent so much time reviewing sites that allowed you to filter RSS feeds, I missed Feed Rinse, which is available at http://www.feedrinse.com/ . And I find when visiting the site now that the service is free, so there’s no time like the present…

To use Feed Rinse you’ll need to register, which requires only a user name, e-mail address, and password. Once you’re registered, you’ll be asked to set up a feed. You can set up one feed at a time or import an OPML file. The site says the free version is limited to five feeds, but since the whole service is free now, I’m not sure what that means.

Anyway, let’s use an example. I’m going to put in the RSS feed for lolcat site I Can Has Cheezburger?. Once I’ve put in the feed Feed Rinse allows me to set up rules.

I can allow feed entries to appear in the feed based on keywords, or block feed entries from the feed based on keywords. I can also block or allow based on the start or end of the feed. I can also narrow the restriction down to body, title, tag, or author. So if I wanted to restrict my lolcat feed just to those pictures with invisible items, I could generate a rule that allowed only those lolcats that have invisible in the title. You can set up one condition or several (block several keywords, allow only a group of keywords, etc.)

Once you’ve set up your filters, Feed Rinse implements them immediately. When you click on the RSS symbol next to the feed name, Feed Rinse gives you the option to get a feed aimed toward several different readers: Google, Bloglines, etc. (There’s a plain one for “other” — I could never get that one to display.)

I liked how easy this was to use, and how the filters were powerful but implemented through a set of simple pulldowns. Recommended if you have a few feeds you want to filter.