There are also plans for another hearing focusing on testimony from small businesses that say they've been affected by internet companies' policies.

Both sessions are likely to tackle some familiar issues. Amazon has been accused of treating third-party sellers poorly, including abrupt halts to sales, downplaying their products in search results or sometimes entering their markets. AmazonBasics in particular tends to compete in areas ranging from phone cables to microwaves. Google has been accused of undermining small shops and playing favorites with its shopping ads, while Facebook's tweaks to its News Feed algorithm have lately prioritized friends over businesses and potentially hurt companies as a result.

Whatever the specific issues, the hearings are more likely than others to have support from both sides of the political aisle. Small business growth is a common talking point for Democrats and Republicans, so any measures that might emerge from the hearings might just get full backing from Congress. The question is whether or not any new bills will emerge. It's easy to grill companies over their policies, but it's another to decide that any problems are large enough to merit legislation.