Today someone asked me to repair a word-document he got by mail. After trying to open it with an uptodate-version of Word (for the case that it's new - not broken), I opened it using an editor and i saw XML, so I renamed it to .xhtml and tried to open it using the firefox. I got an "XML istn't wellformed"-error. Taking a closer look to the file in the editor I recognised that there are a lot linebreaks at the wrong positions - it seems that an emailclient added those for whatever reason. That's an easy problem to solve - using a well known perl-oneliner:
perl -pi.bak -ne "s/\n//g" filename.doc