From Bitcoin Wiki
This pool pays out using a proportional share reward system (your shares / total shares for the round) = % share of the rewards.
The service was first available on July 22nd, 2011.
- TXT/SMS idle miners notification (US numbers only)
- Built on redundant clustered systems, all servers are in a cluster, even the firewall and load balancer.
- Offers managed rig OS (Linux) that features an iPhone/Mobile internet page. You can update and check on your rig from your cell phone. Enables easy overclocking and monitors itself for heat problems.
- Proportional: 3% fee.
-  web site