Big-name brands are seeing the value in niche reach and advertising on smaller sites, reports AdWeek.

While the sites upon which ads for Levi Strauss, Nestle and others are appearing are small, they mostly belong to larger networks. The buying happens through networks such as Glam and Active Athlete, which partner with niche topic writers to sell ads on the sites.

In the case of Glam, Levi's found a partner willing to work to find a new and hopefully more interesting way to advertise on the sites. The network came up with the "What is your denim identity?" execution, which helps people find the jeans right for them.

Advertisers see niche networks as a way to get in front of a small but passionate audience. Networks also make it easy for advertisers to target niche audiences without unnecessary footwork.

Many such sites, however, lack a sales staff that can work with advertisers on the buying process.