At the moment this should only be an issue, if the jurisdiction is Hamburg. AFAIK the BB jurisdiction is Munich.
Heise Verlag has appealed this judgement. As it says in the article, the Judges decision is in opposition to the governing Teledienstgesetz, with regulates these things, and would make it practically unfeasible for anybody to operate a public forum. The operator's responsibility has been previously confirmed by the courts in
Cologne.
In the case in question, a user of a "Heise" forum published a script designed to "swamp" a particular company's server (well known for its "business" practices) with dowlnload requests, similar to a DOS attack, as a sort of revenge. Details of the case can be found
here.
This is typical of judges not having a basic understanding of technical issues and passing judgement on the basis of one general law in opposition to another particular law. In this case, an opinion was not the bone of contention, rather an incitement to an action which could damage the plaintiff's "business".
The law which governs the content of Internet forums is the Teledienstgesetz, not the BGB or the Gewerbegesetze, so it does have precedence in law. The main problem is that judges don't always understand all the laws, but that's why there are higher instances.
As far as BB is concerned: We might insult each other, but I can't remember reading anything here that could be construed as damaging to a radical German businessman's trade, so I wouldn't panic.