It's not necessarily limited to software company anymore

Universities, large organizations with complex corp web sites, ecommerce etc., all need test automation. Automation is expanding its territory rapidly in recent years.

One backside of automation is that the software packages, such as HP QTP, aren't cheap, so it's hard for individuals to pick up at their own costs/paces. The situation is pretty similar to SAP skills. Once you set your feet in, it's a safe place to stay for a while, for now.

I agree with Laotu on this point: If one doesn't have a job, it's not a good direction to persue due to the reasons above.