This thread is old but I developed exactly what you ask for: a webservice, that lets you browse through all of TMDb's database and optionally register and create subscription lists, where you can follow actors and other filmmakers. You will be notified (currently only by email) as soon as new releases are announced. I synchronize my database with TMDb's database once at night, so you only get one email per day maximum with aggregated notifications of all upcoming releases - as long as there were any found that night.

I don't limit my service to actors, directors or some few jobs. I mirror all of TMDb's data and all jobs included.

I recently opened my website for beta users, so be prepared for bugs and updates quite often ;-) I am using it myself every day and would love, if it was of help for other people, too.

Check it out at: https://skriber.tv