Simply put, RSS Re-mixers allow you take multiple feeds and re-mix them into one new feed.
Advanced RSS2Web - helps you to download newsfeeds in RSS and XML format, reformat them according to user-defined HTML templates, upload results to website via shared folder or ftp, work with free newsfeeds and articles available for download and redistribution
Aggrssive - Combine feeds, organize them by TAGGING, find your feeds quickly. Out put any of your feeds to any site on the web just the way you want
Blogdigger Groups - allows you to combine the contents of two or more blogs making the combined content easily accessible all at once. You can create a Blogdigger Group using any blogs that have RSS feeds. Once you specify the feeds that comprise your Blogdigger Group you will be able to view the posts from those feeds, sorted by date, and even export your group in OPML or OCS, or subscribe to your Blogdigger Group as an RSS feed
BlogSieve - a free web-based tool that creates new feeds by filtering, merging and sorting existing feeds. The BlogSieve engine accepts virtually every (valid) feed format, processed results are then exported into any feed format you choose
Collectik.net - helps you find, manage, mix and share media (audio and video) on the net. It’s like mixtapes for podcasts, allowing you to make custom RSS feeds of just what you want to download - anyone (including you) can subscribe to that feed in your podcatcher to get a custom feed of podcasts. Collectik is also a community of audio and video lovers, and it helps you find great content from other Collectik users and Friends. It combines the power of social bookmarking tools, web-based RSS aggregators, and desktop podcatchers
Feed Mix - an RSS editor, which is powerful enough for RSS gurus yet refreshingly easy for RSS first timers. It lets you create, edit and publish the unlimited number of RSS feeds and podcasts. Unique to Feed Mix is its ability to create a new RSS feed or a podcast from several existing feeds. The program gives a great host of useful tools, including a WYSIWYG feed editor, a built-in RSS reader, a blog client, an HTML editor, an image editor, an XML editor and an FTP upload facility. All these and other tools are delivered in an intuitively transparent user interface that makes RSS creation and maintenance surprisingly simple even for a rookie
Feed Pile - pull together the latest news, links, and blogs and share them with your friends
FeedBite.com - share your favorite rss feeds with old friends and new friends. assemble your feeds into categorized groups called bundles. publish your favorite bundles with a single combined rss feed
FeedBlendr - takes the feeds you give it, pulls the individual entries from each of them, attempts to sort them in date order (combined across all feeds) and then provides you with a new, blended feed of all entries
FEEDcombine - a script to combine multiple RSS feeds into one
FeedDigest - mix, filter and republish or syndicate feeds to HTML, JavaScript, WAP or PHP, or to a new feed
FeedJumbler - a web-based application that allows you to convert a RSS or Atom-based feed into RSS, Atom and/or HTML and JavaScript, Merge several RSS or Atom-based feeds into one combined RSS and/or Atom feed, put an RSS feed (or merged feed) on your webpage using an IFrame or JavaScript)
FeedShake - can merge, sort and filter multiple RSS feeds
FrankenFeed - Egor can generate a master feed for you. What is a master feed? Do you have several feeds on the same topic that you want to share with someone (or just use yourself)? Egor will combine multiple feeds into a single simple feed. You can always come back and easily add or delete the feeds
KickRSS - takes multiple RSS or ATOM feeds, combines them, and displays them as a single RSS feed or a webpage at an easy-to-remember URL
mapufacture - a GeoRSS aggregator. Here you can layer multiple GeoRSS feeds from different sources into a single map, and search the database of GeoRSS feeds by keyword and location. Search results are themselves available as GeoRSS feeds. If you do want to create a map, there is a simple registration process
MyGlu - allows you to define your own list of feeds, merge them into a single feed, and place the results on your web page. Perl script
Peoplefeeds - allows people to aggregate their generated content in one place and allows others to identify what is relevant to them (via a watchlist), regardless of whether it’s a bookmark, a photo, or a blog entry. There are two basic parts to the Peoplefeeds experience: personal content aggregation and discovery of other people’s personal content
RSS DJ - a new style of RSS aggregator. “In fact, we call it an RSS Mixer, and you are the DJ (well, maybe a PJ for Podcast Jockey). Here are some of the coolest things that RSS DJ does and lets you do… Take any text based RSS feed (blogs, news feeds, anything), and automatically convert them to spoken word MP3 podcasts!. Filter out advertisements from RSS Feeds. Scrape web pages for those RSS feeds that don’t provide their entire stories but only a summary or a link. Create your own RSS DJ “Mixes” combining feeds based on tags, freshness, and peer ratings. You can even interweave songs and tracks from our FREE Creative Commons licensed music library”
RSS Mix - mix any number of RSS feeds into one unique new feed
RSS Replay - an extension for Dreamweaver MX, MX2004, and Dreamweeaver 8 that allows you to place content from RSS feeds into your Web page layouts. RSS Replay works with AJAX-JavaScript to incorporate content from RSS & Atom feeds from both your own Web site (local feeds) and other Web sites (remote feeds)
RSS-Merge - a simple Magpie-based script which can be used to merge multiple feeds into a single feed and sort the feed contents based on the date
RSSmesh - a PHP script used to merge multiple RSS feeds into a single RSS feed
SuprGlu - gathers your RSS and ATOM feed content from popular webservices and publishes them in one convenient place. Presents your content with simple, great looking templates which you can customize. Is free to use
xFruits - Mix and make mixes of feeds for blog, mobile and start pages