Laid off,could I use EAD to stay in even with no job?

Just got laid off. I am guessing H1B is not available any more. But I have an EAD with my hu*****and's I140 petition. Could I use this EAD as my current status for staying in USA even with no job?

If I find a job later, I know I can use my EAD to work. But I read one previous post from mytwocents, it said that I need to register with the employer. How could it be handle? Is it related to tax purpose?

Thanks a lot!!