Der Spiegel is reporting that someone wants a German "wordmark" on the "@" sign (original in German). The company involved has the rather unusual name "@ T.E.L.L.", where the initials apparently stand for "Tradinghouse for Exclusive Luxury Labels".
Trademark has such a bad reputation these days that the above news is bound to elicit some knee-jerk reactions along the lines of "OMIGAWD they're gonna take control of that word/letter/sign/color" and "what could go wrong?".
First off, the answer to "what could go wrong" is "everything", and it applies pretty much everywhere, not just trademarks. There's always bound to be some entitled jerk who is going to take the whole arm when you give them a hand. IP just happens to be talked about a bit more these days.
Second, it is important to understand that trademark gives you exclusivity in specific domains, and in connection to products. It's not like they're given blanket ownership of the "@" symbol for every use everywhere forever. If they use the "@" symbol to mark their products, and their customers recognise their products, then why shouldn't they get some protection?
It is important to note, though, that trademark, when applied correctly, is not supposed to protect the company from its competitors, but to protect customers from confusion.