Over the past few days I have been using Phind.com as the default Firefox search engine which was providing excellent search results. However, today my IP was blocked and banned. Just a reminder when using new shiny tools, you can be blocked from access.
I have no prob with outside US IPs (even with several different VPN)
I suspect they block you since you are using it as a default: I did it too but realized is a total waste of (their) cpu and (their) money to use it for dumb queries, so I removed it as a default and use is only when I do really need it's (great) results
If I am seeing it correctly my advice for Phind will be to communicate/educate users :)