Who doesn't like swag? In the past, we've only gotten these exhibitor and vendor gifts mostly at conferences and trade shows we attend. But, of course, that's now gone away.   Or has it?   Subscription boxes are the latest publishing trend. FIPP, the international trade group, just did a whole special report on them, complete with case studies. Basically, publishers send subscribers and would-be subscribers physical boxes of cool items. Yes, it's mostly been consumer up to this point, but it doesn't really have to be.   The idea has proven an effective one for our homebound times. A month ago, I wrote about a new online show called The Present starring magician Heider Guimaraes, where ticket holders are mailed a box with surprise contents that they are directed not to open until their Zoom show starts.   "How do you reach out of the computer and into the audience?" asked Matt Shakman, artistic director of the Geffen Playhouse in ...