Congratulations! But what does 20 million people online actually mean? Does it mean 20 million people with the status "online" or that 20 million Skype users are not offline? Or does it mean, as your blog suggests, that 20 million people are talking at the same time? If the latter is the case, there must be at least 200 million Skype users who are not offline at the same time!
I am looking for the answer to this question for a long time already.

I wanted to say that I believe that that number represents the total number of skype users who are logged into the skype servers at any given time

‘20 million’ means 20 million people signed in to Skype at the same time. They may not all be calling or IMing at the same time, but they’re able to do so. I hope that clarifies things

Thanks, it's clear to me now.

Does that mean Skype needs to upgrade its infrastructure to withstand this large traffic, to prevent lots of drop calls? Can you kindly let me know what's Skype been doing in regard to this issue?

@devi.joshi because Skype’s a peer-to-peer app, you actually benefit from having lots of people online at once

If you’re having problems with dropped calls, you should check out our call quality guide – let me know if that helps.

Helped a little bit, but not to my expectations.
Anyways Congratulations on achieving this milestone.

SKYPE saved my long distance relationship!! thank you so much!

Congratulations on the 20 Million! However, I have noticed a significant degradation in call quality above 15 million users, when calling from Iraq on my computer to US telephones, both landlines but particularly cellphones. Calls are almost impossible as the numbers grow into the 17million and 18 millions. The mechanical sounds in the voices on both ends, and the inability to hear at all most times. Is there a fix to this? Or does capacity need to be increased by the company?

@misnu43 take a look at my earlier comment