Anything can be done but it really depends on whether the work involved is justified.
Something like this could only be available to website members to stop people signing up with somebody elses email. Really, to make it useful we'd want something that emailed you when the particular thing you wanted was entered. To do this properly would require selection of species via a proper species list. And that requires a proper taxanomic list; not strictly true but I'd always envisaged everything being cleverly tied together.
It really depends on how much use it gets to be honest. I mean, if you just want to know a new ad has been placed, I would be willing to do that, but content specific matching requires more trouble than it's currently worth.