Northampton 1, Amherst 0

Northampton, like Amherst, has special regulations for dealing in second-hand stuff. A while ago, I asked the Powers That Be in Northampton a similar question to the one I asked of Amherst:

If I were to buy and sell "secondhand articles" on Ebay.... would this city ordinance apply to me?
--
§ 202-7. License required.
It shall be unlawful for any person to be a collector of, dealer in, or keeper of a shop for the purchase, sale, or barter of rags, paper, old metals, junk, or secondhand articles without first obtaining a license from the City Council as provided in Chapter 140 of the Massachusetts General Laws. No person shall purchase or receive by barter within the limits of this City any of the articles mentioned above without first procuring such a license.
--
I guess the question is: what's the definition of a "dealer in" ? Is there some dollar amount that would make me a dealer in secondhand articles?

The next day I got this reply:

In order to be licensed for secondhand articles, you would need to have a place of business, that would be zoned for this type of business and file a Business Certificate. A dealer in second articles is a person who buys and sells second hand articles, such as used clothing, used books, records, etc., there is no dollar amount associated with being a secondhand dealer. The license fee for a secondhand dealers license is $25.00 a year, and the business certificate fee is $50.00. The business certificate is good for four years.

Wendy Mazza
City Clerk

Just to be sure, I asked:

So... am I allowed to buy and sell used articles on Ebay, through the mail, out of my home? Or does this apply only to "walk-in" businesses, with customers that come to a storefront?

... and got this reply 10 minutes later:

This would only apply to walk-in businesses, with customers that do come to a storefront.
The only way you would need to have a second-hand license is if you had to file a business certificate to set up a business checking account and the bank required you to provide them with necessary documentation that you where in business.

Wendy Mazza

So: two emails to one person in Northampton and a day later I get a "yes, you are allowed."

I first sent essentially the same question to Amherst Town Hall on September 5'th. 20 days later, it's bounced around to the following people in the Amherst bureaucracy (these are all the people cc:ed on the dozen or so emails I've sent/received on this, so far):
Patricia J Olanyk, Larry Shaffer, Gail Weston, Chris Brestrep, Caroyln Holstein, Bonny Weeks, Jonathan Tucker, and the entire Amherst Select Board.

And I'm still waiting for a straightforward answer to my original question, which maybe I can restate here: "Under what conditions does buying and selling used stuff from my home constitute a 'business', for which I need to get permits and stuff?"