Exclude some, not all, user profiles from search engine results
There is and there is not, there are two sides of that question.

Bad side is - external search engines are just that: external. You can send them suggestion but you cannot make sure they respect them.

Good side is - you can create a field, and if it's checked output: &lt;meta name="robots" content="noindex" /&gt; Some search engines, including Google, Bing and apparently Yahoo! (can't find a link for that one), will respect that.