Google Instant added more advanced search completion and prediction to the Google interface. But when it launched, many asked why certain predictions and completions were not coming up. Google Instant shows search results as you type, but not for lesbian and other terms like bisexual.
One such example is typing in [lesbian], when you enter 'leb' the suggestions stop coming up. Entering the whole word doesn't even render results, you have to hit enter:
Google recently said in a Google Web Search Help thread that the lesbian example is a bug and Google will fix it. Kelly from Google said:
We've received some questions about why typing [lesbian] into the search box does not instantly show results. This is a bug and we are working to see if we can fix it. In the meantime, these results are available but require you to hit Enter.
She then goes on to explain why other results may not show search results:
If the results for a particular query seem pornographic, our algorithms may remove that query from autocomplete even if the query itself wouldn't otherwise violate our policies. This system is neither perfect nor instantaneous, and we will continue to work to make it better.
Kelly links to a document on how Google Instant works for additional information.
Forum discussion at Google Web Search Help.
Update: Seconds after writing this I wondered how Google could "fix" it to show search results for the term [lesbians] when the search leads to pornographic web sites. I decided to blog this question at Search Engine Land.