Blog networks are often described as "small world" social networks where links are primarily created towards similar-minded individuals and well-connected bloggers. Examining a portion of the US blogosphere on several months, we find that bloggers relate to each other in a relatively local fashion, overwhelmingly and preferentially establishing links towards a limited neighborhood rather than the whole network. Furthermore, while long-distance interactions may indeed be dominated by homophily and authority effects, we show that close neighborhoods feature significantly more horizontal and diversified interactions — thereby challenging the conjecture of a widespread balkanization of Internet communities. We shed further light on this issue by describing the dual evolution of social and semantic proximity before and after two individuals interact with each other. We discuss in particular whether interactions are preceded or followed by a structural "contraction" and/or by an increasing similarity of the surrounding local social network.