If you are using Content, K2 and got wrong SEF URL when publishing to Twitter, Facebook, LinkedIn, ... please just put obSocialSubmit system plugin to the last in System Plugin ordering.
This problem occurs when you have SEF on with stock Joomla SEF, sh404SEF, AceSEF.
Here is the detaisl instruction:
Recently, plenty of obRSS customers asked for Image Tag (image node) in feed for iPhone and/or Android app.
obRSS is a powerful and flexible RSS Feed Syndicate solution with its core functions, it makes adding Image Tag/Node to each feed item pretty easy. We get it done within 15 minutes includes building installation packages time for both addon & plugin versions.
Be notice: addon version with prefix: obrss_addon_* is for obRSS 1.9 or older; while plugin version with prefix: plg_obrss_* is for obRSS 3.x which need to be installed via regular Joomla installation. More instruction can be found at How to install obRSS addon?
Existing customer can download this latest K2 addon/plugin for obRSS at http://foob.la/download
Auto Import items for K2 is easy with obFullTextRSS & K2 plugin.
Recently, K2 released 2.6.1 version which works with Joomla 3.0, it was a good news for the community.
Unfortunately, Joomlaworks team made some changes to that K2 CCK extension and K2 plugin couldn't work with that new version.
After a few days of hard working, Kha Nguyen, an awesome developer of ours has got K2 plugin for obFullTextRSS done, it is now working perfectly with K2 2.6.1.
Existing customer can get it from the download area. More information about this K2 auto import items solution please take a look at http://foobla.com/joomla/obfulltextrss.html
Last week, we've released 2.1 version for K2 RSS Feed add-on for obRSS at http://foobla.com/blog/k2-rss-feeds-21-released.html
Early this week, Claudio Benvenuti, a dear customer of ours, requested a new feature to be able to show/hide images from K2 full text, but still showing image from K2 image tab. We have got K2 RSS Feed 2.2 done which added that requested feature from our dear customer.
Existing customer can download the update from the download area at http://foob.la/download. New customer can get it at the obRSS store page
K2 RSS Feeds by obRSS 2.1 released. Here is changelogs information:
Lots of options to ordering K2 items in your RSS Feed, includes Randomize which allow you to have fresh K2 RSS Feed even when you don't have new content :)
You can create RSS Feeds with additional elements which useful to transfer your K2 items to other platform (Android App, iPhone iOS App, other websites,...).

Existing customer can download the latest version from the download area, new customer can get it at obRSS page
K2 auto social poster solution by obSocialSubmit with K2 plugin.
Please see the screenshot to see how K2 plugin works in obSocialSubmit.
VirtueMart RSS Feed is much easier, more control with obRSS Joomla Extension.
obRSS is the best RSS Feed Syndicate extension for Joomla. VirtueMart add-on adds ability to obRSS for creating ultimate RSS Feed for VirtueMart extension.
Not only creating ultimate RSS Feed for VirtueMart, you can take advantages from obRSS such as: Merge RSS Feeds together into a big one OR manage & display all of yours RSS Feed stuff into one place in your Joomla site front-end.
K2 RSS Feed is much easier, more control with obRSS Joomla Extension.
obRSS is the best RSS Feed Syndicate extension for Joomla. K2 add-on adds ability to obRSS for creating ultimate RSS Feed for K2 extension.
Not only creating ultimate RSS Feed for K2, you can take advantages from obRSS such as: Merge RSS Feeds together into a big one OR manage & display all of yours RSS Feed stuff into one place in your Joomla site front-end.
Joomla K2 is one of the top north CCK extension for Joomla, we can use it for making news site, blog, catalog site,... out of the box.
Lots of Joomla webmasters have been asking me to make modifications to K2 CCK to make it post to Twitter, Facebook, LinkedIn, Google Buzz, ... every K2 item posted.

It's now easy and out-of-box with a solution from foobla by using obSocialSubmit with K2 add-on. Your K2 items will be in Twitter, Facebook, Google Buzz, LinkedIn, Ping.fm, ... automatically.
Joomla K2 RSS Feed is now more flexible with Joomla RSS Feed Creator + K2 RSS Feed addon. We have just released new addon for Joomla RSS Feed Creator by foobla, it will add K2 support to this RSS Syndicate extension.
We can create unlimited Feeds for K2, select multiple categories, authors, tags,...
"--- WHAT IS K2? ---
The powerful content component for Joomla!
K2 provides an out-of-the box integrated solution featuring rich content forms for items (think of Joomla! articles with additional fields for article images, videos, image galleries and attachments), nested-level categories, tags, comments, a system to extend the item base form with additional fields (similar to CCK for those acquainted with Drupal), a powerful plugin API to extend item, category and user forms, ACL, frontend editing, sub-templates and a lot more!
Using K2, you can transform your Joomla! website to a news/magazine site with author blogs, product catalogs, work portfolio, knowledge base, download/document manager, directory listing, event listing and more, all this bundled under one package!
Give K2 a try and you'll instantly love it! It's easy to use and fun to develop websites with! If you need any help or want to contribute to the project, join us at the K2 community." - Joomla Extensions Directory
To get a copy of this addon, please visit Joomla RSS Feed Creator product page.