Latitude, a UK-based search marketing firm, has appointed LongAcre partners to advice on a possible £60m sale.Groups such as WPP, Aegis, Publicis and Omnicom are among potential bidders. ValueClick, a US-based online marketing group, has also been named as a potential bidder. 3i, Hg Capital and Kleinwort Capital were named as among private equity funds that could be interested.