Taylor Banks is a Hacker, Entrepreneur and Location-independent Startup Mentor. Founder @ ACE Hackware, Organizer and Mentor @dc404 and @cloudmeetup. Mastermind Coach. Passionate about Startups. Frequent Speaker on Anonymity, Privacy, and Security. Download slides and watch videos of my security and privacy talks at Black Hat, B-Sides, DEF CON, The Georgia Institute of Technology, Hacker Halted, ISACA, ISSA, LayerOne, and ShmooCon on SlideShare and YouTube.
]Like most of the folks who've already replied to your question, I also use bit.ly with my own domain. If your intent is the shortest possible URLs and you don't care about using your own vanity domain, bit.ly also owns the "j.mp" domain, which can be interchanged anywhere you otherwise see "bit.ly".
However, if you're looking for more detailed metrics, you might also want to consider looking at some of the ad tracker tools internet marketers use, as they support features like advanced campaign management and duplicate detection.
hyperTracker (www.hyperTracker.com) provides some pretty detailed metrics, and they also provide guidance for using your own short domain(s) to masquerade URLs created with their service.
While the development of a "freemium version" might help you build a customer base, it could consume a significant amount of your time and money without the assurance that your free users would every become paying customers.
Since you're a one person operation, and running on limited capital, I'd suggest a different approach. If indeed you've gotten good traction with big companies, I'd approach one ore more of these companies and ask them to invest in the continuing development of your product up-front, in exchange for a significant discount on the per-user licensing costs. This will both serve as validation that your application is as valuable to your target customer base as you believe it to be, and would also provide you the additional income necessary to move forward.
You might also put serious consideration into trying to find a salesperson who would work with you for either straight commission (if you expect your deals to be large enough to make this attractive), or for equity. In either case, this would enable you to significantly increase the number of paying customers you can target with your unique solution.
I'd be more than happy to discuss these and other strategies in detail with you if you'd like to schedule a call with me. Good luck!
To echo Dan and Chris' sentiments, customers and cash-flow are your most important goals. That said, I would strongly suggest you spend more time focusing on customer development than cash-flow, as a business without cash-flow can survive with investment, but a business without customers is unlikely to survive at all.
As an excellent resource, I'd suggest you take a look at The Entrepreneur's Guide to Customer Development, available at http://www.custdev.com/ (I'm not affiliated in any way, just a fan).
Of course, if you'd like to chat more about startup focus, I'm happy to setup a call to discuss tactics I've used to build our customer base AND revenues by more than 300% year over year.
These days, people are inundated with email. Instead of using your newsletter to duplicate the content on your blog, use your newsletter to pique your readers' interest.
Give them just enough information to make them want more. Ask them questions, and tell them how to find the answers within your relevant blog posts, tweets or Facebook status updates.
Use your newsletter to remind your audience to stay engaged with you; avoid using it as a means of engagement, as you're more likely to find people filing it away, ignoring it, or worse, unsubscribing.
Hope that helps?
If you'd like to chat more about email marketing and newsletters, feel free to schedule a call with me to see how I maintain high open and click rates with my own ever-growing customer mailing list.
Get in front of your users!
As a startup founder, no matter how far it is outside your comfort zone, the best way to get your first customer is by getting in front of people.
I'd suggest joining your local Chamber of Commerce and attending local meetups. In most cities, you should be able to find at least a small group of like-minded people interested in the problem you're solving. If you can't do it in person, consider doing a webinar or Google Hangout instead.
If you know who your user is, your next step is to make sure they understand what you're selling. The best way to do that is by asking smart questions, and ultimately, testing and refining your elevator pitch.
Not up to in-person networking? Find a co-founder who is! ;)
Need help finding meetups? Want to learn how to quickly, easily and inexpensively host a webinar or hangout? Feel free to schedule a call with me for any questions you may have.