TL;DR
Alpha Geeks are people who first try new technology stuff. To steer your learning investment, you need to keep an eye on what they are doing. The post is based on a remarkable book written by Chad Fowler, The Passionate Programmer.
Investment is a living thing. After you do your research on what to learn next, you start your learning process. But this should not be set it and forget it, because the software testing market changes and you then you must pivot your learning. Monitoring what software testing alpha geeks are doing could give you information about what is happening in the software testing market.
For example, sixteen years ago, Selenium was initially developed by Jason Huggins as an internal tool at ThoughtWorks. Following ThoughtWorks or Jason, you would be first to know about this technology. Bach and Bolton Rapid Software Testing is something similar in the work of testing methodologies. My new bet is José Valim, the creator of the Elixir programming language. Do not forget about the local community. Zeljko Filipin is my domestic Alpha Geek.
How to get to Alpha Geeks? The cheapest way is to monitor technology news aggregator sites like HackerNews or Lobsters. When you spot that some news got traction, start to follow that person or company blog via RSS feed. Or even better, you have some new testing ideas? Try to become one of the software testing Alfa Geeks!