A couple years ago (around 2007) when I made Naija Lingo, Jekajo.com and Igbadun.com I used to read a lot of techcrunch. One story I kept seeing over and over again was how some team would make an app, shoot out a couple emails with links of their new product and by the time they woke up or to be more specific "by the next day", they had a couple thousand users.
This is not correct! There is a process to releasing software. In small companies it can take minutes and big companies it can take days to review and deploy a release. The mistake I used to make with all my sites is that I would work on them all day, and then shoot out emails to friends and family in the middle of the night. I guess my thought was they could attend to my cool website first thing when they woke, and second I did not want to be twiddling my thumbs watching users sign up. I just wanted to wake up in the morning and BAM! 1000 users. Please do not do this.
There are two times you should never launch software.
1. Before you go to sleep
2. Before you go on holiday/weekend
The best time to launch/release software is when you are awake, vigilant and available. From my experience no matter how much I tested my applications before hand, there was always something I had not accounted for, something always broke and I would not find out till 8 hours later after I had woken up. So instead of getting all excited about all the signups I got, I panicked because of all the emails I got about people having trouble signing up. Secondly people getting emails of your new application at 7 in the morning is not also the smartest. People are getting ready for school, work, preparing for their lives ahead, your email could easily get overlooked and forgotten. I usually suggest sending it around 1pm on a Tuesday. Just when people come back from lunch and will get bored after 3pm and are looking for something to distract them, they can easily see your launch email.
Launch and release new applications and features during the day so you also have bandwidth to handle unforeseen situations that might come up.