&gt;<i>I don&#x27;t really know why you seem to have an axe to grind here.</i><p>Not sure about the &quot;axe to grind&quot; thing -- I didn&#x27;t call any names, and it kind of calls for people to see any kind of reply from me as further &quot;aggression&quot;. I merely stated my opinion based on what I&#x27;ve seen 15+ years in IT (including using QT to write some KDE API based apps).<p>I believe I have a quite good understanding on where QT stands in the &quot;commercial apps&quot; landscape, and common isn&#x27;t the word I&#x27;d use for it. Skype would be the biggest success story, if they still use it, and it looks quite different from the regular QT&#x2F;Windows look (which is what we were discussing).<p>So, just by Skype alone sure, you&#x27;ll find &quot;most Windows PCs used by regular consumers have [a copy] of Qt on them&quot;, but that&#x27;s not enough to call it common in my book. Most regular PC also have had Java applet SDK and even JREs, and one could cite a few apps using it, but few would call Swing &quot;popular&quot; in the desktop space.<p>As for Qt being a &quot;800k developer ecosystem&quot;, a lot of them work on internal enterprise tools, automation software and stuff like that, which has been a traditional market for TrollTech and QT in past decades. Then there&#x27;s always KDE of course too.