CloudMade e-mailed users today to let them know that as of May 1st, only enterprise services plans will be available. In particulare the company will stop serving Map Tile, Geocoding, Routing and Vector Stream Server requests coming from API keys. Users have the option of upgrading to an enterprise plan for those with 10,000,000 or more transactions per month or going elsewhere for these services. Cloudmade points those choosing the latter option to MapBox and MapQuest and HackerNews points to even more options.
I don't see any information about the change on the CloudMade website.
via Eric Jiang via @cageyjames