RSS 2.0: 200+ ways to find, aggregate, read, generate, manage, mix, filter, splice, tag, validate, publish, syndicate, promote, back-up & share feeds

"RSS 2.0" is almost a pleonasm. It makes that content unbundles, and it's doing the same with services. RSS is everywhere nowadays, and it's driving many of the innovations in the sociosphere. Although active use is still an innovators' thing, there's hardly a content owner or digital service provider who isn't exploring its endless opportunities.
All major browsers have included RSS reading functionalities, and services like start pages and some streaming content providers (Vpod!) are further popularizing RSS by making it a seemless experience. So do instant messengers and many mobile portals. Where it isn't it will be. This category is an awkward mix between high level solutions and accidental, sometimes obscure, snippets of well applied code. Close to a 130 additions in this update, in italic.

2rsscom - RSS feed directory
Activeroll - Linkroll wizard
Activerssreader - RSS reader (Windows)
Addtoany - Meta RSS button linking to major bookmarking services
Afeeda - RSS mixer
Aggrssive - Share your mixed feeds
Agilerss - RSS reader (Linux)
Akregator - RSS reader (Linux)
Alertbear - Customize your feeds
Alesti - Feed reader
Almondrocks - Share feeds
Anothr - Manage & read feeds in Skype messenger
Atiki - Tag based feed search
Attensa - Read & share feeds enterprise-wide through Outlook
Autopinger - Ping service
Awasu - RSS reader (Windows)
Beanrocket - News reader
Beeplet~ - Set up reminders & get alerts
Blastfeed - Only get the feeds that matter to you
Blogbridge - Feed reader
Blogdigger - RSS feed directory
Blogexpress - Feed reader
Blogflux - RSS ping tool
Bloglines - RSS readers (web based, mobile)
Blogsieve - RSS mixer
Blogstreet - RSS feed directory
Bottomfeeder - RSS reader (cross platform)
Briz - RSS reader (Windows)
Changedetection - Create RSS from websites
Changenotes - Create RSS from websites
Crackfeed - RSS reader (Windows)
Egress - Mobile RSS reader
Evolvepoint - Create, track or find feeds
Febber~ - Enterprise RSS aggregation solutions
Feed2js - RSS javascript generator
Feed43 - Web page & Blog2RSS
Feedamasser - RSS reader (Windows)
Feedbite - Share, bundle & syndicate your feeds
Feedblendr - Blend several feeds into 1
Feedbucket - Feed reader Web-based
Feedbuddy - Find new friends with similar feed needs
Feedburner - Manage your rss & podcast feeds
Feedbutler - Social feed reader
Feedbutton - Meta RSS button
Feedcatch - Manage your feeds
Feedcollectors - Collects & socializes your feeds
Feedcombine - RSS mixer
Feedcraft - Create, manage, deliver & track feeds
Feedcrier - Get RSS news alerts through your IM
Feedcycle - Serialize your feeds
Feeddemon - RSS reader (Windows)
Feeddigest - Mix, filter & republish or syndicate feeds on your website
Feed-directory - Filtered feed search
Feederreader - RSS reader (mobile)
Feedexpress - RSS reader (Windows)
Feedeye - Read feeds
Feedfeeds - RSS reader (Ajax)
Feedfindings - RSS filter
Feedfire - HTML2RSS
Feedgit - Meta feed search engine
Feedicon - Create your feed icon - RSS
Feedicons - RSS button
Feedity - Web2rss
Feedjumbler - Generate, mix or splice RSS or Atom feeds into one RSS or Atom feed
Feedlet - Feed reader
Feedlinx - Find feeds on any website
Feedlounge - Feed reader
Feedmailr - Feed2mail
Feedmeme - Share feed apps
Feedostyle - Personalize your feeds
Feedpass - Create a landing page for your RSS feeds
Feedpath - Social feed reader
Feedping - Submit your feed to major directories
Feedpublish - Mix your feeds
Feedraider - Share your mixed feeds
Feedrinse - Filter your most interesting feeds
Feedroll - RSS2JS converter
Feeds20 - Folksonomied feed reader
Feeds2be - Create feeds from websites that don't have any
Feeds4all~ - Feed aggregator
Feedsforme - Search feeds
Feedshake - RSS mixer
Feedshark - Submit RSS feed to directories
Feedshow - Feed reader + shares rev with publishers
Feedsplitter - RSS2HTML2JS newsreader
Feedsweep - Publish RSS news feeds
Feedtier - Web page & Blog2RSS
Feedtwister - Process feeds
Feedvalidator - Feed validator
Feedvault - Back-up & share OPML
Feedwhip - Track changes on your favourite websites
Feedxs - Republish your feeds
Feedxs~ - Create personal feeds (without website), submit thru messenger
Feedyes - Gives feeds to sites without feeds
Flitic - Manage, tag & find feeds
Freerange - RSS reader (mobile)
Free-rss - RSS creator, editor, publisher, validator & viewer
Fwicki - RSS reader (web based)
Geofeed - Create geography-aware feeds
Googlereader - RSS reader (web based)
Grazr - Compile your own RSS widget
Greatnews - RSS reader (Windows)
Gregarius - Feed reader
Happyfish - RSS reader (Windows)
Humanizedreader - Feed aggregator with decent design
Ifeedreaders - Meta linkpage to RSS & bookmarking services
Immediat - Messenger notifications of feeds
Infominder - Create RSS from websites
Instantfeed - Messenger notifications of feeds
Intravnews - RSS reader (Windows)
Ipings - Ping service
Istalkr - Aggregate & organize rss services that you & your friends subscribe to
Juice - RSS reader (Windows)
Just-ping - Ping service
Kickrss - Blend several feeds into 1
Kingping - Ping service
Linkrss - Create, store & syndicate your own rss feeds
Litefeeds - RSS reader (mobile)
Mappedup~* - Map your feed sources geographically
Metarss - Reader, (re)publisher, meta search & keyword feed generator
Metaweather - Put aggregated weather feeds on your site
Mobispine - Mobile feed browser
Multirss - Meta button to major RSS readers
Mysindicaat - RSS reader (web based)
Netnewswire - RSS reader (OS X)
Newsaloud - RSS2voice
Newsfire - RSS reader (OS X)
Newsgator - RSS reader (web & mobile)
Newslife - RSS reader (OS X)
Newzpile - Aggregates tags-based feeds from many sources
Nooked - Manage & commercialize your feeds
Octora - Search & share feed bookmarks
Odiogo - Convert feeds to speech
Omea - Manage & enhance your feeds
Opmlicons - OPML Icon project
Opmlloader - OPML reader Web based
Opmlmmanager - OPML reader Web based
Opmlsurfer - Read OPML Web based
Opmlvalidator - OPML validator
Opmlworkstation - Edit, manage, convert & share OPML + PPT2OPML
Opod - Ajax OPML & RSS widget
Optimal - OPML widget
Ozmozr - Import, store, share & manage feeds in bulk or individually
Particls - RSS reader (Windows)
Peoplefeeds - Aggregate personal content
Pheedfire - Manage, measure & monetize your feeds
Philter - Flash feed reader
Phonefeeds - Read your feeds on your phone
Pingoat - RSS ping tool
Pingomatic - RSS ping tool
Ping-service~ - RSS ping tool
Pixelnews - RSS reader (OS X)
Podbasket - Converts audio into feeds
Poderator - Store podcasts & create XML
Ponyfish - Create feeds from any website
Publish - Create feed from anywhere
Queoo - RSS to email, messenger
Quicknews - RSS reader (mobile)
Quicksub - Meta RSS button
Rapidfeeds - Publish feeds without tech know-how
Reblog - Republish your feeds
Reblogger* - Collect, filter, sort, index & publish feeds
Redland - Feed validator
Refilter - Filter your feeds
R-mail - Rss2email
Rojo - RSS reader (web based)
RSS mixer - Aggregate all your feeds in 1
Rss2gif - Auto-updated RSS in image
Rss2pdf - Convert feeds to PDF
Rssbandit - Feed reader
Rssbus - Connect & share your data thru feeds
Rsscache - Cache your feeds
Rssdj - Share your mixed feeds
Rssfwd - RSS to email
Rsshut - Read & search feeds
Rssmad - Feed reader & archive
Rssmesh - RSS mixer
Rssmix - Mix your feeds
Rssor - Collect, read & share feeds
Rssowl - RSS reader (cross platform)
Rsspanelx - Script to display all feed formats from originating website
Rsspect - HTML2RSS & RSS2JS
Rssreader - Feed reader
Rsstojson - RSS2JSON
Rubhub - Ping service
Search4rss - Search feeds
Shareopml - Search & share OPML
Sharpreader - RSS reader (Windows)
Shrook - RSS reader (OS X)
Simplefeed - RSS-based marketing solutions
Snarfer - RSS reader (Windows)
Snownews - RSS reader (Linux)
Solosub - Meta button to major RSS readers
Speedyfeed - Share your mixed feeds
Straw - RSS reader (Linux)
Streamy - Read feeds
Syndic8 - RSS feed directory
Syn-sub - Meta button to major RSS readers
Thunderbird - Webmail solution
Tickermyfeed - Feed generator
TinytinyRSS - Feed reader
Trackengine - Create RSS from websites
Trackle - Create RSS from websites
Trawlr - Read feeds
Ufeed - Get RSS feeds in your own page
Vienna - RSS reader (OS X)
Watchthatpage - Create RSS from websites
Weblogalot - RSS feed directory
Weblogs - RSS feed directory
Wizzrss - Read feeds
Worklight - Feed reader widget also connecting to intranet
Wotzwot - HTML2RSS
Xfruits* - Mix, make & share feeds
Yodpod - Feed reader
Yutter - RSS feed2email subscription
Zaptxt - RSS to email, sms, messenger
Zaptxt - Rss2email + mobile rss reader

Italic = new. Update 061224, 070119, 070303, 070517 (corrected 070527), 060827.