My domain is up for renewal soon and I recently received a very official looking letter from a company called Domain Renewal Group. On the surface it looks like a renewal notice from my registrar but if you read more closely mention that the letter "isn't an invoice" and that if you return the form and pay them you'd be transferring the domain from your current registrar to them. Never mind that the price they're asking is almost 5 times higher than what my actual register wants for an annual renewal.
I bet this catches plenty of people out - that's what their business model depends on. Bottom feeding scum.
Plenty of others have blogged about these guys as well, but I thought I'd add my voice. As more people learn about these kinds of scams they become less effective.