The new About page is great.
Towards the bottom of the page it mentions what kinds of questions are acceptable and what are not. Common questions we get at Stack Overflow are appropriate for other Stack Exchange sites like Programmers, Pro Webmasters, Code Review, etc. Since these are in the Stack Exchange family of sites, why not take this opportunity to make (new) users aware of these sites and what kind of questions they are appropriate for.
One idea would be to alter the "Don't ask about..." list to include questions these sites are better suited for (naturally brighter minds than mine can come up with better verbiage):
- Questions asking for a code review. We have a much better place for that.
- Algorithm and data structure concepts. Our Programmers can assist you with that.
- Managing a website you own. We know some Pro Webmasters who [whatever]
Another possibility would be to just add a section that mentions related sites. This would be above and in addition to the general Stack Exchange promotion at the bottom of the page.
If the goal of the About page is to improve the quality of questions and answers at Stack Overflow, why not help users find places where questions that are off-topic at Stack Overflow but on-topic elsewhere in the Stack Exchange network? It helps to raise the quality of Q&A at Stack Overflow, helps to reduce the "you're asking in the wrong place" comments and other related issues, and helps the other Stack Exchange sites thrive.