To most Twitter users, URL link shorteners are a convenient way to stuff more into a 140-character message. But a proposed class action lawsuit filed on Monday alleges that the social media service is using them in violation of the Electronic Communications Privacy Act and California's privacy law.

The complaint brought in federal court in San Francisco from Wilford Raney and others similarly situated is claiming that despite Twitter's assurances that users are allowed to "talk privately” among one another, "Twitter surreptitiously eavesdrops on its users’ private Direct Message communications. As soon as a user sends a Direct Message, Twitter intercepts, reads, and, at times, even alters the message."

The lawsuit uses a link to The New York Times as an example.

If a user privately tells a follower through the service to check out a story on nytimes.com, providing a full URL, Twitter will modify this into a custom link such as “http:/t.co/CL2SKBxr1s” (while still displaying the text “www.nytimes.com” to its users).

Twitter algorithms are making the change, but nevertheless, the lawsuit asserts that it's wrong. By sending users to Twitter’s analytics servers before passing them on to the linked-to website, Twitter is allegedly benefiting by demonstrating to The New York Times and others where the source of the traffic is. "The end result is that Twitter can negotiate better advertising rates," says the lawsuit.

Do Twitter's practices amount to wiretapping?

Some legal scholars have argued that computers scanning communications don't amount to interception, but two years ago, Google failed to get a judge to dismiss a class action lawsuit over the Web giant's peek into user gmail for keywords so as to deliver custom advertising. In that case, the judge looked at whether the interception happened in the "ordinary course of business" — an exemption under the ECPA — and ruled that the "limitation...means that the...provider...must demonstrate that the interception facilitated the communication service or was incidental to the functioning of the...service."

Google later got a victory when a judge denied class certification.

The new lawsuit aims to represent two classes — every American on Twitter who has ever received a direct message and every American on Twitter who has ever sent a direct message. The claimed damages are as high as $100 per day for each Twitter user whose privacy was violated. Here's the full complaint.

A spokesperson for Twitter declined to comment about a lawsuit that comes right on the heels of word that the company is working with publishers including The New York Times on an "instant article" format for quicker loading of stories.