selective subscriptions: are they possible?

Can one site be set up to allow people to subscribe to specific things?

More sites are showing up with multiple purposes and I am thinking about doing one of my own. One problem I’m noticing is that I get updates on all sorts of things that are of no interest to me. Example:

If I set up a site to review laptops, phones and tablets, can I set things up to allow a user to subscribe for just tablet updates?

Since this is just an initial inquiry, detailed instructions aren’t necessary. It’d be nice to know if it’s feasible, easy, complicated, “do-able but not a good idea” etc.