Loopt, the mobile social network which is backed by Sequoia and NEA, has filed a lawsuit against Loop’d Network, a social network for action sports athletes and enthusiasts, over alleged trademark infringement, alleging that the two names are too similar and cause confusion. Loopt is asking the court to enjoin Loop’d Network from continuing to use the name, and is also seeking damages and three times the profit that Loop’d Network has earned, PEHub reports.

Loopt says it started talking to Loop’d last fall, but says that the two companies were unable to reach an agreement. Loop’d Network, which is incorporated under the name Sponsorhouse, rebranded itself in November last year, aiming for a wider audience. The story says this case is more than just a branding confusion: “At issue is whether a general social networking site such as Loopt is the same thing as a targeted social network such as Loop’d Network.”

Loopt has raised almost $20 million from Y Combinator, New Enterprise Associates and Sequoia Capital. Loop’d Network has raised $1.9 million from undisclosed angel investors.