We use GitHub for our open source project. The core functionality is great (in terms of source control) and it is simple to setup and contribute in. It would be nice if their wiki was searchable. We had to create our own one in another application.
Mailchimp is awesome. It's really easy to navigate and create anything from an A-B split campaign to automated messaging that runs after certain events. Pricing is really reasonable for bigger mailing lists and more functionality. Highly recommend this application.
A very flexible project management tool. If you need flexibility with some templating this is a good bet from a project management perspective. I will say that I wish the task items on a card supported multi-lines / paragraph breaks but otherwise no complaints.
It's flash based which stinks but still the most productive wireframing tool I have found so far. It treads the line between enough out of the box elements and enough flexibility to do the job without getting in your way.
Trello makes it easy for me to stay organized and to remember what I have left to work on. It's very intuitive to use. I really like being able to separate out my different projects into different boards, and it is a great tool for collaborating with others. It did take me a little while to learn how to use all of the features, but that didn't slow me down from getting started with it.
I use Trello almost every day to keep up with my to-do lists and ideas. It has a clean layout, and it's easy to move lists and cards around. I like how quickly I can add members to different boards and cards. There are some features available on it that I don't use. Overall, I'm able to make it work well for my needs.
I used this app at a hackathon a few months ago and really liked it. The support team is super responsive. It is definitely the fastest way I know of to get a quick landing page up and in front of people.
We've been using bitbucket here at Salespatron.com to manage our code ever since we started work on the development. Bitbucket provides the best of both worlds, it is free and hence great for new bootstrapped businesses all the while providing functionality (like private repo) which you can only get with other code management vendors. +1!
VWO is one of simplest A/B testing tools out there in the market! We've been using this tool for testing traffic on our site salespatron.com and we have seen some really good results. Our conversion rates went from 7.6% to 13.2% within a week of testing. Highly recommended!
I've been a big fan of Balsamiq's simplicity! The best tool used by designers has been "pen and paper" throughout decades due to the minimalism the medium provides. Online prorotyping can never match the simplicity of a pen and paper but Balsamiq comes very close. Love their simplicity! When starting the work on designing my app, Salespatron.com, this is the first site I went to and was not disappointed.
BrowserStack has made life very simple for our tech team. We were always shuffling between various laptops and browsers to test our new code, for our product Salespatron.com, properly before moving the code from dev to production. With their amazing API, our work has been moving very fast. It is amazing how such a simple service can be so useful and not thought of before. These guys deserve all the success.