Web analytics and optimization firm Omniture is acquiring rival Visual Sciences (fka WebSideStory) in a $394 million cash and stock deal announced yesterday evening. Omniture believes the deal will be financially accretive and allow it to better take advantage of the growing online advertising market. It also sees an opportunity to cross-sell its product portfolio to a combined 4,000 customers. Completion is expected in early-to-mid 2008, pending shareholder and regulatory approval. Release. The deal is the latest in a consolidating space. Visual Sciences itself was bought by WebSideStory last year for $57.3 million, before the whole firm changed its name back to Visual Sciences. Google (NSDQ: GOOG) is also involved via its 2005 acquisition of Urchin, although as a recent IDG story notes, there’s been frustration among Urchin customers about the slow pace at which Google has developed the product.