Thankfully, no. But it is prevalent.
Point is, when we use the word popular, we generally mean that it is used
due to it being liked. You really never hear the word describe something
which is just common. "Prevalent" or just "common" is a better choice
there.
We often use the word 'popular' for something that is prevalent
through free choice, such as consumer goods.
Fowler, in 'Modern English Usage' uses the term 'popular' to describe
usage of the word inoxicated of which he says 'so long popular as to
be not now recognizable for a medical term at all', here the word
'popular' is used to describe the common usage of a word in everyday
language by ordinary people. The word 'intoxicated' is so commonly
used that Fowler describes it as 'popular'.
In contrast, the word 'common' as an adjective means 'shared alike by
all the persons of things in question, or by all humankind'.
'Prevalent' would also be inappropriate to describe a Newsreader
application, since it would indicate too large a market share as
though to not use the 'prevalent' application should mark one out as
odd.
Popular is the correct term then in the context of describing a
Newsreader with a large user-base.
Matt