I don't get it

Could someone please, please, please tell me why so many blogs I read are written by people who shop at stores like M@cy's and get their coffee from places like $tarbucks?

I don't understand that.

Edit 12/22: I don't know why I thought people would understand what I wrote. But what I was really wanting to know, is why people use the @ instead of "a" and the $ instead of "s" when they write the names of companies. I can't figure it out.