Pleasanton-based Mercado, a developer of search and navigation and merchandising software, has been acquired by Omniture, a provider of web analytics software. Omniture said late Monday that it would pay approximately $6.5M in cash and assumption of certain related operating liabilities for Mercado. Mercado was venture backed by The Challenge Fund, Conesus Business Group, Eucalyptus Ventures, Pitango Venture Capital, Star Ventures, and Valley Venture Capital. Mercado had last raised funding in 2006, when it pulled in $11.5M. The firm also has operations in Israel.