Dear Google, Apple, Facebook, Twitter and other top technology companies: Over the past six months, many of you revealed that the percentage of underrepresented minority employees in your ranks is in the single digits. Most of you acknowledged that you’re out of step with the diversity of your own users. And many of you said the No. 1 cause is the pipeline: low numbers of qualified applicants who are female or of color, especially for tech positions. Well, it’s time to put your vast resources to work on filling that pipeline.