Any way to add few more details to the site meta? or Global site fields?

Hello,

I want to Add few more details to the new site signup page.

I will show all the blogs signedup in the site in main site with available plugins. But also i want to ask the person name, location he is signingup from and few more details at the signup stage.

So in the main site, global blogs listing page, i want to show all user details with blog name, avatar and all.

Is there anyway to do that? If we create a custom field ? If we ask to fill that custom field in the user's blog anywhere. Can we call that custom field to display in thew main blog ?

I'm thinking like if there is a site meta for every single site and if there is a way to let users fill that site meta at signup stage, how to display that data in all blogs listing page in site.

thanks