This video from Matt Cutts explains why those excluded pages still show up in Google’s index, but without a title or snippet.
Basically it turns out that if they find links to a page they’ll still index it using the rationale that, if others link to it, it may have some value to some searchers.
If you truly DO NOT want that page to appear in the index, there are two ways to handle it:
- Add a noindex meta tag to the page itself.
- Use Google’s removal request tool
For the latter you’d want to be absolutely sure that you want that page gone from the index forever, as you’d have to jump trough some hoops to try and get it re-included. If you’re easily able to do #1 that may be the better bet.
