I validated my feed here:
Recommendations
This feed is valid, but interoperability with the widest range of feed readers could be improved by implementing the following recommendations.
line 31, column 0: content:encoded should not contain iframe tag (8 occurrences) [help]
<content:encoded><![CDATA[<p><!–[if IE]><iframe allowTransparency=”true” …Source: http://hadarweitzman.com/feed
Have you tried:
– deactivating all plugins to see if this resolves the problem. If this works, re-activate the plugins one by one until you find the problematic plugin(s).
– switching to the Twenty Ten theme to rule out any theme-specific problems.
– resetting the plugins folder by FTP or PhpMyAdmin. Sometimes, an apparently inactive plugin can still cause problems.
The feed shows full posts in IE. In FF it shows summaries because that is the FF does feeds.