When I hit the online checkout with two shirts in my basket, the dreaded "Create a login" form appeared. Click went the "X" on the browser window.
Before my gentle reader exercises her/his right to do the same with this browser window, allow me the disclaimer that this isn't a hot-house flower rant against the drudgery of unnecessary keystrokes and mouse-clicks. Rather, I think it serves as a good example of not understanding what business you're in--as in a chain supermarket vs. food co-op dichotomy.
In most scenarios, a login implies things like identity within a membership, exclusivity, access to privileged information, the ability to create content. That's why we have them for our work computers, bank accounts, social networks, etc. Requiring a login to purchase something online only makes sense if I'm eligible for special treatment (e.g. free shipping). There's no such incentive in this case, particularly not for a first-time, perhaps only-time customer.
There's a practical dimension to such philosophical quibbling, however. The problem with such forced "memberships" is that the login is useless to the would-be "member" unless s/he returns on a fairly frequent basis. Until that time, another, potentially orphaned-from-birth username-password combination has been spawned. If appropriately robust and unique, the liklihood of its usefulness will be slim (because--seriously, now--how often do folks write down logins they may never use again?). If not robust or unique, the username and password pair is actually a liability--something that could be more easily cracked and fraudulently used. Not much of a choice, that.
I suppose there's plenty of room for hair-splitting on the differences between members and customers, but I do think that recurrance is a key component. Logins don't, by themselves, particularly encourage recurrance--and, as in my stubborn case, can prevent it entirely.
Thoughts on computers, companies, and the equally puzzling humans who interact with them