HTTP/2 is a new version of the popular protocol that is for communication between the web server and the browser. It is a lower level technology than Drupal, so taking HTTP/2 into use does not require any modifications to your application or installation of Drupal modules. Drupal 8 introduces the request-response model to Drupal developers, but on a higher level - this is not to be confused with HTTP/1.1 vs. HTTP/2.
Drupal 8 release date is November 19th 2015. That's the big day that thousands of people have been working toward. It'll be a major release - arguably the biggest change to Drupal itself in it's history. Read the details on the Drupal 8 launch article.
Along with Drupal 8 release there has been a lot of noise made about headless Drupal with the REST API. Headless Drupal maybe a great choice for data driven use (such as web applications or mobile apps), but for content driven applications (web sites) a pure headless implementation offers little improvement over more traditional site building methods.
The relationship of Drupal and Acquia is somewhat unclear to newcomers to Drupal. When they get into Drupal they're whole heartedly welcomed to the Open Source community known as Drupal. But the company Acquia keeps popping up when talks of Drupal and Business arise. Let's try to make this a bit more clear
On the internet information is free, but still locked down in relational database formats of CMSes like Drupal or WordPress. Exporting and importing content can be a chore, but agreeing on a proven format will help content migration projects.
WordPress Extended RSS is an extension to the RSS format and could be a universal language for content migrations. It is widely deployed in the WordPress world and offers enough structure for migrating common content structures like news articles and content pages.
We're well into 2015 and it seems that at the PHP 7 crew is holding on to their promise of releasing PHP on time this year. A few days back the PHP team tagged Release Candidate 1 for PHP 7 for release. This is a first sign of an actual release, since there is nothing stopping the PHP 7.0.0 RC1 being the release that actually ships. Probably it won't. but it's looking very good.