Heroku is a cloud-based hosting platform for Ruby on Rails applications. It allows developers to deploy their Rails apps through Git and manage hosting without having to deal with servers. Developers can run rake tasks, access the application console, interact with databases, add gems, and scale dynos and workers as needed when traffic increases. Heroku also offers add-ons for services like databases, email delivery, search, and caching.
don't do heavy calculations in your web process
instead let a background process do the job
use background jobs when request run longer than 500ms
fetching data from remote APIs, reading RSS feeds, resizing images, and uploading data to S3
beta testers are currently testing the rails 3 implementation on heroku
heroku makes sure you can always use the last stable rails version
unless you purchased something on heroku
you can use amazon service for this