Newspaper ad revenues are falling about as quickly as my golf scores are climbing. Teeing up a joint effort to attract advertisers through an online network is a foursome of publishers: Gannett (NYSE: GCI), New York Times (NYSE: NYT), Tribune, and Hearst.

The network, called QuadrantOne, will be composed of about 120 national newspapers. The Times' lead newspaper of the same name won't be included, nor will Gannett's USA Today, since both papers already have their own online sales operations.

This is the latest manifestation of a near-desperation attempt by newspapers to expand their online products as rapidly as they can. A separate group of papers already has teamed up with Yahoo! (Nasdaq: YHOO) in an effort that primarily has been selling classified ads but now is moving into other areas.

My Foolish friends know, of course, why this is happening: In the face of the gradual newspaper ad revenue slide, their websites' ad sales are climbing quickly.

Only a tiny fraction of most newspaper companies' revenues still comes from the online side. Even a mighty effort to boost online sales will have limited consequences -- yet another reason for Fools to continue to give a very wide berth to newspaper investments.

For related Foolishness:

Fool contributor David Lee Smith doesn't own shares in any company mentioned. He does welcome your questions and comments. Yahoo! is a former Motley Fool Stock Advisor recommendation. The Fool has a banner disclosure policy.