Allow users to subscribe to certain search queries

[fatlotus]

Primarily, this is a cost problem:

Our sendgrid free tier only grants us 25,000 emails/month ~ 35 emails/hour. Currently, we get a listing every 15-30 minutes or so, meaning about 1-4 emails/hour, plus some number for inquiries. If every user got an email for every listing, then we could only have 10 subscribers site-wide.

Hence:

• Would "daily digest" suffice? Do people need real-time notification of new listings?
• Would something like ServiceWorker offline notifications work?
  (Looking at our metrics, 60% of people use Chrome, but only 8% of those use it on mobile. Would notifications on a desktop still be as useful?)

Food for thought.

[tranv94]

Interesting issue. What about allowing a user to subscribe to a keyword? It could reduce email usage (e.g. furniture being narrowed down to couch). Maybe letting a user select between keyword and categories?

Also possibly letting a user select how often they are notified could work as well. Some people could be looking for a specific item for immediate use, versus others who are generally interested in a category of items.

[fatlotus]

Hmm, that's an idea. Maybe people would only want to know about the next N things in a given category?

[tranv94]

That could work, it would be redundant and a waste to send an item the user has already seen, but why only N things? There could also be a link to "see more.."
I think a digest would be best because I feel like most users wouldn't want an email each time an item in their category is uploaded. You could also group categories the user is subscribed into one email.

[fatlotus]

Ah- I meant only having subscriptions last for a finite amount of time. While digesting might work, it seems like a lot of listings get posted about very quickly, so I'm not sure how much of a time delay we can afford.

There's also still the concern of cost: even if each person only gets an email every day, that's limiting us to ~800 subscribers. By limiting the time frame of a subscription, we make sure that people are subscribed only while they're looking for a particular category.

Alternatively, it could fit into the "wanted" category of listings. Maybe we play matchmaker if we see two similar listings in the same category?