I have very picky criteria for picking an online vendor, whether it's for personal use or for raw supplies for my store. I insist on clear, easy-to-use shopping cart systems. An "account" area, so I can go back and check on previous orders. A flexible catalog system, so I can find what I'm looking for whether it's by weight, fiber content, or other search criteria. I think it's a given that it must work properly, and accurately. They should have decent prices, and their shipping charge must be reasonable.
Oh yeah, and they need to have something *in stock* for me to buy.
I'm not going to name names, but for the past year and a half I have been growing increasingly irritated with the yarn supplier I use. They run out of colors frequently. Apparently they've never heard of creating an "order point", i.e. if your stock drops to a certain number, you order more. I see inSANEly ridiculous back-order dates for FEBRUARY, right now. WTF? Are they shearing the sheep themselves? If I want to make a black sweater, I really have to wait till February? For BLACK?
Yes, I'm in the position where I could dye it up myself. My point is, I shouldn't have to. If they're counting on their consistently low prices to retain their customers, they're really kidding themselves. Right now, one of my raw wool suppliers also carries yarn. I don't buy from them, because they carry "luxury" yarn brands, and the prices reflect that. Their free shipping option is insanely slow, and their paid options are expensive. But if I have to, I will switch. Because I've never seen them run out of Cascade 220. In ANY color.
Get your acts together people. Folks are eyeing their purchases a little more closely these days. Billing errors are not going to be overlooked. Shortages and frequent out-of-stocks are just going to send them somewhere else. You could have the finest "Dollar Store" around, but if a person walks in ready to spend, and all they find is one lonely plastic bowl on the shelf, they'll turn around and shop somewhere else.