Can I sell my database if it's no longer making money?

Do both. Verify but continue to let them use the site in a limited capacity or even better have a message at the top reminding them to verify as they use the site. Keeping the message up will drive the right people to verify and the wrong people to continue to not verify.

I'm a developer at Clarity and was involved in the development of this feature. This specific feature was developed in house. We keep event logs around for a log of things and this feature is built on top of that. When you visit a certain page showing interest in an expert, we'll schedule a job to send this email. A few hours later, when the job runs, it verifies a few things against other logs and we send the email if it's a good fit. These days I would take a good look at Intercom (https://www.intercom.io/) to do this. They recently came out with event tracking (http://insideintercom.io/power-of-behavior-driven-messaging) making this kind of feature a lot easier to build.

Your emails have a lot of room for improvement. You have to: 1) Give a 1 sentence intro 2) Get right to the point quickly in a clear and easy to understand way. Eliminate all the long winded and confusing language (i.e. everything in quotes: "business attitudes towards....provision") 3) Most people will be very wary of clicking links in a cold-call email. Both because it would take time, and because they're expecting to see a huge survey and/or a crappy app made by some schmo. To get around that negative bias, include an impressive screenshot of your app, and include all the questions of your survey, or if it is super long, include just the most interesting questions to pique their interest. Have those things be in-line, not as attachments. Doing these things will help make them curious and help convince them that it's worth clicking on the link (they'll trust you more). 4) If allowed in this project, look into other routes other than emails. For instance: A) Post it to relevant subreddits (https://www.reddit.com/r/AlphaAndBetaUsers, https://www.reddit.com/r/sideproject, etc.). B) Mail a small gift (e.g. a small chocolate) to companies, and have a note on the chocolate with an intro and a link (use an URL shortener) and QR code. Even if they don't go to the link on the note, you could do a follow up email in which you mention that you previously sent them the gift, which will increase your success.

The typical consultant answer is 'test it' but there are some good places to start. People generally start checking email when they show up to work (yes that includes personal). Sending around 8:30AM will give you a good shot of being at the top of their inbox then. Another good time is before lunch break. Shoot for something around 12:00PM for this. If you have an email provider that allows you to adapt your send to the local time, use that. But if not, go for EST. Close to 50% of the US population lives in that, with another 30% one hour behind in central.

I have. You will experience a much better return on investment, and your customers will have a much better experience when you take advantage of audience segmenting -- which Customer.io and the likes offer. To be far, you can achieve this same result with tools like Aweber, but they are not as intuitive because, frankly, they were made long before the best practice of segmented and event-based email notifications were established and as matured as they are now. Depending on your list size, a move can be a hassle. But, if you have a plan on how to monetize that list, and deliver incredible value to your subscribers, I would encourage you to move to platform that can slice and dice your list how you need. Any other questions, feel free to drop a note or schedule a call. -Shaun