Healthchecks.io - Monitor your cron jobs and scheduled tasks, get notified when they fail.
Full-Text RSS - Full-Text RSS transforms partial feeds into full-text feeds.
Pingbreak - Pingbreak is an original and free monitoring service.
Inoreader - Dive into your favorite content. The content reader for power users who want to save time.
DownDetector - A simple service to tell you whether a website is down.
Feed.exileed.com - This service transmits your favorite social networks by RSS.