Should startups fear big companies?

I just read a good post about how big companies have been poaching great ideas from startups. So, should emerging entrepreneurs be worried or so anything to avoid having their ideas get stolen? I say, no. I do believe that the small guys are able to recognize consumer frustrations and respond quickly while the Fortune 500 has resources but a giant hairball that makes it almost impossible to deliver. Little guys - just keep delivering and know that the right solution to a real problem will set the stage for success (assuming the rest of the business model makes sense).