WebGazer - Monitor your website's availability with WebGazer, review its performance and get instant notifications when your website goes down. No installation required and free plan available.
Topicbox - Put team emails into one centralized, searchable place
Hyperping - Cheap uptime and performance monitoring with detailed reporting and flexible alerting
InboxSDK - First usable API to write Gmail Apps for 1B active users
NIXStats - SaaS monitoring tool for window/linux servers and websites. Think up-time robot but with more features.
Front - multi-channel inbox service for collaborative teams