It's much more than tags - in-text exact entities, deep categorization, related news, etc :)
The exact disambiguation of mentioned concepts and entities is what is exciting and underused by web developers right now.
Andraz Tori, CTO at Zemanta
I think sense disambiguation is certainly one of the most interesting applications of semantic technologies. Here at TQ, the focus tends to be on the exploitation of referential semantics and structured data to establish master data models, merge data models and provide a platform for model driven application development and analytics. However, the focus here tends to be more towards corporate IT than mainstream web dev.
How best do you think this can be leveraged by folks that are interested in associating commonality within text (clustering by topic)?