How can I make this app more useful?

Okay, there is my feedback.

1. The navigation doesn't work correctly. When I try to browse contributors, I click this button, then click on somebody to see his/her profile. When I click back button in the browser I see projects again, not contributors.
2. There is no filtering by skillz/programming languages/something else. I can't go through all profiles, it's not practical. I would like to select, say "Python", "Vue" and you show me only those who have skills in this.
3. Also, many people don't have a good profile. Just "programming" is not enough.
4. It would be nice to specify in profiles which project people would prefer to work on - like somebody seeks for an opportunity to work on a game project, and other is okay with financial project etc.
5. Also, it's very important to specify how much time a person can contribute and which condition - somebody wants to be a cofounder, somebody just wants to help.
6. Projects themselves should have more information and be searchable. It's hard to find a project, there is no classifications, no tags.
   Hope it helps. Good luck!

connects developers who want to work on a side project with developers

Are the people posting developers also developers themselves or are they non-technical people looking for developers? It's subtle but it's makes a difference. Maybe you can match people who have posts that are similar?

A link to the project would be helpful so I can actually see it.

How often are connections / introductions made through your project?

Behind the scenes, maybe you could read through each submission and manually try to make suggestions for Mary to meet Joe, or Sally to connect with Mark, etc.

This way, you help accelerate the value your service adds for your customers!

Seems like there aren't that many projects yet. As that increases the app will be more useful.