Facebook is getting ready to fight back against Yahoo, which sued it yesterday for patent infringement.

That's according to Om Malik, citing reliable sources close to Facebook. The company apparently thinks it has enough patents to fight back.

Good move.

If Facebook fights and the case actually goes to trial, Yahoo could end up with all sorts of trouble:

  • Its patents could be challenged and invalidated.
  • Yahoo might be found to infringe upon Facebook's patents, in which case payment might go the other way.
  • There's a remote chance that embarrassing information -- like emails -- could come out during discovery, or that Yahoo employees might have to testify.

This is why companies typically resort to patent litigation as an absolute last resort. And why patent cases are almost always settled before trial.

Facebook had no comment on the report.