How many satellites can we safely fit in Earth orbit?

Just 10 years ago, a mere thousand or so operational satellites may have orbited our planet, but there will be tens or even hundreds of thousands a decade from now. Experts have been sounding alarm bells for years that Earth orbit is getting a bit too crowded. So how many satellites can we actually launch to space before it gets to be too much? More

(Source: N2YO.com - Mar 1)