The “Semantic Templates” extension displays HTML templates from a LESS installation in TYPO3 pages.
LESS is a web application to create HTML templates and fill them with data from the semantic web (linked data: RDF, RDFa; and SPARQL query results).
You can use it to display data from i.e. the Wikipedia on your TYPO3 page. Your page updates automatically when the data in Wikipedia change, and with LESS you have a central place to manage the layout of your template. Other people can improve your templates or add new ones, ready for you to use.
Apart from Wikipedia, you can make use of any data that are available as Linked Data (RDF/RDFa) or via SPARQL queries. FOAF profiles of people are a good example for RDF data.