I have a calendaring site (won't mention it here b/c I don't want to be seen as plugging it) that has been generating revenue from ads and subscriptions for 26 years now. At its peak, well over 100k/yr but now more like 15k/yr for the past 5 years. Still a very steady income b/c the site is sticky. The only expense I have is about $3k every 36/mo for VPS hosting. At this point the code base is so mature that I only do minimal user support. I've looked into selling but people only want to offer 2x annual revenue. Why would I do that when I can just hold onto it for another year? I wish more people saw the math your way.
I would have several questions before negotiating seriously, and I could actually be in the market for such a beast.
At what multiple would you be comfortable considering selling? If revenue has dropped 85% from its peak, have you identified the cause of the drop? Has it been steady that past five years? Do you have a record of the time spent on it, or does it just feel minimal? How much of revenue is from ads vs subscriptions? Is it sticky mainly because a user can’t export things and import them to Google Calendar or something?
Is it custom software, heavily customized software, or are you basically selling the calendaring component of something like Citadel or Horde? What languages are in use? Does the buyer get just the site or full ownership of the codebase and the rights to derive new products and services from it? Does it come with the domain and trademarks?
Are you selling outright, or are you reserving some royalty for yourself?
What does the handover look like? Does the buyer just get an email with URLs and login credentials, or do you plan on familiarizing a buyer with the whole thing?
The main reason this is an issue is that it's a lemon market. Many sellers claim their sites will require "no time to maintain" and that future returns will likely continue, but it's often a lie and thus you don't get the multiple that is truly justified. Even without lies, no one knows the truth of your business like you do. The unfortunate result of this -- and I've been in a similar position in the past -- is that you are incentivized to lazily run things into the ground slowly rather than find a new owner who may bring new passion.