Panda Cloud Antivirus is a free version of Panda's security software. It is cloud-based, meaning that scanning of the files is handled on a remote server rather than on a user's machine. This results in less "bloat" as seen by the end-user. The cloud technology is based on Panda's Collective Intelligence.
Panda Cloud anti-virus is considered to be a new breed of security software since it relies on cloud (internet), the community, and collective intelligence, rather than just signatures..It requires an internet connection to function, though if internet is unavailable it runs using a cache of well-known threats.
Beta 3 (private) added Windows 7 and 64-bit support 
One major review deemed Panda Cloud Antivirus as clean, fast, simple, and easy to use, and offering good detection rates. The same review scores Panda 98.87% in malware detection and 71.4% in malicious URL detection. Overall score was 85%, a strong protection factor considering it is freeware.
Another review (by PC World) found it to be #1 in the new free anti-virus products.