But if you have a special character in you topic title, you get an error
Invalid Unicode value in one or more parameters /intent/tweet?source=webclient&text=IPad+3+-++Verbindungsabbr%FCche+Beim+Mobilfunk-Surfen+-+http%3A%2F%2Fwww.computerguard.de%2Fipad-3-verbindungsabbrueche-beim-mobilfunk-surfen-vt7636.html
The problem here was this "Verbindungsabbr%FCche" = Verbindungsabbrüche
So üöäß and maybe some other are not working.
Could be it is a problem of twitter.
But maybe we can use clean name for this.
EDIT: If you cange this, it is working fine...
Not sure it will work in all old browsers
OPEN templates\default\social_bookmarks.tpl
FIND
<a href="http://twitter.com/home?status={TOPIC_TITLE_ENC}%20-%20{TOPIC_URL_ENC}" rel="nofollow" target="_blank"><img src="{FULL_SITE_PATH}images/social_bm/sb_twitter.png" alt="Twitter" title="Twitter" border="0" /></a>
REPLACE WITH