I've been praising (and using) linode for years, and have referred many (oh, at least.. 15 or so) people to them since I started using them in the summer of 2003.
And *NOW* they start using a referral program. I think I was customer #12 or #17... somewhere in that range, back when they only had 4 servers, in one datacenter. Now they've got ... over 150 servers in 4 datacenters. Crazy.
And they keep giving free upgrades. 2 months ago, everyone got a 20% diskspace boost. Less than a year ago, it was 20% extra RAM. Then 25% extra diskspace. And even more RAM and bandwidth, at exactly one year ago this week.
In the last year, a Linode512 became a Linode720, with 200MB extra RAM, 8GB extra diskspace. (My original account was a Linode128, which over 5 years of these free system upgrades, became a Linode 720. I actually downgraded my account because it was much more than I needed.)
If anyone's interested:
Linode Virtual Servers