This one is really pretty simple, we don’t need Mirriam-Webster or other sources,

Group Buys are orders placed by a group of folks – either working with a retailer or working around them by going direct to the manufacturer/distributor or other source.

“It used to be” that there was some affinity among the groups. Group member might have been part of a business or social organization, a local craft guild. But generally speaking they KNEW each other and often as not, functioned in many ways cooperatively.

Now, all it takes it Internet access and 5 minutes to set up a group on one of the many online services that support “groups” and poof you are instantly able to organize group buys.

Some of these groups are well run and organized and businesslike in how they operate. Others are not.

Quite simply, they exist so must be considered as a potential competitor for those who really are in business.