The internet firm has appointed Lean Mean Fighting Machine to develop a digital strategy to help it compete more aggressively for revenue against rivals such as Google.
It is understood that Lean Mean Fighting Machine has been briefed to create a series of campaigns promoting Yahoo!'s display, classified and search offering to big-name brands.
Yahoo! offers a range of commercial opportunities across its sites, including shopping-comparison service Kelkoo, social calendar upcoming.org and Flickr, the photo-sharing site.
Last month Yahoo! also acquired US-based college and high-school sports website Rivals to boost its sports publishing and online communities business. It intends to capitalise on the site's popularity to build stronger communities among its users and increase ad revenue.
Yahoo! is currently expanding the amount of video content available via its web portal to tempt advertisers disgruntled with TV. It also recently launched search service Panama in a bid to break Google's dominance of the £2bn online advertising sector.
Lean Mean Fighting Machine declined to comment.