We recently disallowed a wide variety of pages for www.udemy.com which we do not want google indexing (e.g., /tags or /lectures). Basically we don't want to spread our link juice around to all these pages that are never going to rank. We want to keep it focused on our core pages which are for our courses.

We've added them as disallows in robots.txt, but after 2-3 weeks google is still showing them in it's index. When we lookup "site: udemy.com", for example, Google currently shows ~650,000 pages indexed... when really it should only be showing ~5,000 pages indexed.

As another example, if you search for "site:udemy.com/tag", google shows 129,000 results. We've definitely added "/tag" into our robots.txt properly, so this should not be happening... Google showed be showing 0 results.

Any ideas re: how we get Google to pay attention and re-index our site properly?