Tuesday to Thursday, but if you are targeting a specific industry or region, consider factors like their workweek or peak engagement times, but for most audiences, mid-week is a safe bet.
It all depends on your goal. If you want to take the top spots, it's better to post on weekends (there’s less competition, but also less traffic). If you need traffic, then Tuesday to Thursday is better, but the competition is tougher.
1. Go and create a product with a scheduled launch date.
2. Make a pre-launch badge — this will help you track your position in the "Upcoming Launches" section.
3. Check the upcoming launches — if you see several big players with 300 upvotes already listed next to you, consider moving your launch date. I am actually thinking of postponing the launch of seatext.com because I noticed two major competitors launching next week. The thing is, having big product launches near your small startup can be a death sentence. These companies might have already paid 100 Indian hackers to generate 300 upvotes using their bots — and they've even shown you that they're ready for a fight. So why engage in a battle if you're not willing to pay for those shady services? Just choose another day.