The Nielsen Company has been working on building up its mobile side lately. Following its recent combo offering of PC web and mobile web traffic, the ratings service is expanding its 10-year-old online audience profiling system @Plan to mobile, Mediapost reports. Its Mobile@Plan will cover demographic data on users of 200 major mobile sites and will provide details on a thousand data points related to users entertainment, personal events, media use and purchases and connect it with subjects like travel, auto and finance. Nielsen will also integrate the mobile data with information from its regular PC-based @Plan.

While Nielsen has been working on bridging its PC and mobile information with its TV broadcast ratings data, the move comes as audience targeting space in general has heated up. For example, on Wednesday, online rival comScore (NSDQ: SCOR) bought Seattle-based mobile measurement firm M:Metrics for $44.3 million in cash, signaling the increased importance of mobile to advertisers. That’s quite a good deal, considering that Nielsen paid $440 million for mobile metrics firm Telephia last summer.

• Nielsen Takes ‘Next Step’ In Audience Measurement, Combines Mobile Web Traffic With PC Online Use