1.   Amanda Mack of Durham does not like to buy things online, but she has traded balloon-flower seeds for marigold seeds at a swap site.

2.   But Jonathan Gaw, who tracks e-commerce for International Data Corp. in Mountain View, Calif., is dismissive of Internet swap sites.

3.   But on most swap sites, you can trade one used CD for another of about the same age and popularity.

4.   But swap sites need to persuade people to engage in a form of commerce that many left on the playground when they outgrew trading marbles and baseball cards.

5.   Despite the controversies, swap sites are proving popular.

6.   Going on line, Robertson downloads a song from a swap site, then transfers it instantly to a music player the size of a coaster.

7.   Students in the minor will also examine issues like intellectual property, online pornography and the music swap site Napster.