Building a Twitter Reader / SMTP Mailer

So I want to build an app that constantly monitors a certain hashtag/phase like #cookies and sends out an email to me (and anyone else who signs up on the site) every day with a list of all the tweets.

I have some Ruby/Rails experience and was considering building this on Heroku, but I was wondering if there was an easier platform to build it on, like say, Goog开发者_开发百科le App Engine (which I know very little about)

Assuming you want this to be a web application (not necessarily true from your description), I'd recommend Rails. You have some experience with it, and it's a solid platform. Heroku should work fine for this, but it's certainly not the only viable option. I'm not an expert on Heroku, and I don't know much about your app other than its primary function, so I couldn't tell you if Heroku is the optimal choice. As for Google App Engine, I'm pretty ignorant, but I've heard Rails isn't currently its sweet spot. (Just hearsay.) You could also consider a VPS, which is probably more work but also very educational.

The app itself should be pretty easy to use. Plug in to the Twitter Search API (http://dev.twitter.com/doc/get/search) or piggyback off some third-party Twitter aggregator. Then set up a cron job that accesses whatever data stream you've picked (Twitter API or third-party) and plug the results into ActionMailer.