The Tweetpaths website is currently hosted using a Heroku free plan. A couple of days ago, Heroku announced changes to their pricing plans, including changes to the free tier. These changes mean that I will not be able to effectively continue running Tweetpaths using the free tier, as it will only be able to be available for 18 hours a day.
As a result of this, I have decided that I will no longer continue running the Tweetpaths website, and will shut down the website sometime towards the end of June. While I could possibly have looked around for another free or low cost plan, I have decided that I no longer have the time or the interest to keep maintaining Tweetpaths.
I will however make the Tweetpaths code open source and publish it somewhere, most likely on GitHub. This will probably happen in the next week or so, I just need to tidy up the code to remove things specific to my implementation (e.g. it currently has my email address hard coded for sending exceptions). If anyone else wishes to take the code and run their own version of the Tweetpaths website they will be able to do this.
I have only recently renewed the tweetpaths.com domain for another year. After Tweetpaths is shutdown I will set up a static page at tweetpaths.com linking to Tweetpaths alternatives and (if there are any) other people's Tweetpaths implementations.
I should point out that I have no problems with the pricing changes Heroku have announced. It seems to me that the free tier was only ever intended for development and experimentation, and not for running full time websites like Tweetpaths, even ones that aren't part of a business or making money. Given this, the changes they have made are perfectly understandable.
UPDATE: I have now published the Tweetpaths code. See this blog post for details.