I started over a year ago with the work on a side project called Sponsorgap - a platform for creators to find a sponsor. It was profitable from the early beginning on and in the last months I passed 500$ MRR. It sounds like a success but to tell the truth, it is really hard work and often comes with some ups and a lot of downs. Here are some key learning lessons for me so far and things that have worked for me -... Source: almost 3 years ago

Hey folks, I am the founder of Sponsorgap and from time to time I run this little experiment in different communities to help creators find a sponsor. So if you are looking for brands buying ads and sponsorships in newsletter just name your newsletter and industry field in this thread and I try to put a list together with potential sponsors for you. Source: about 3 years ago

SponsorGap: SponsorGap is where newsletter and website creators find their next sponsor, post their open ad slots and brands publish their open sponsorships. Source: over 3 years ago

I'll update this if I find more. For now, this seems to be a partial solution. It's a Gmail add on (except I don't use Gmail) that adds reminders. The options when setting reminders include cancelling it if someone replies, and to remind everyone in the thread. If you combine those two, it seems like — if you use Gmail's web client and have $23/month you're dying to get rid of — a decent way to add the feature. Source: over 1 year ago