No no no sovellus is program, as a sofware developer in Finland my self, we develop apps and programs they are not always synonymous, appi is usually used here, to separate them from programs. This is a bit ridiculous coming from DL
Me too, i.e. I am also a software developer in Finland. And I use words like sovellus, ohjelma, sovelma, lisäosa and try to use them in the senses defined in the dictionaries published by TIVIA (Finnish Information Processing Association). Having said that I understand average Joe or Jane (Matti Meikäläinen or Maija Meikäläinen) has hard time to see the differences.
I use word applikaatio only in mathematics, when speaking about applying a function to something. And I never use word appi or äppi (expect when speaking out aloud the menus in the newest Mac OSes, what a FUBAR by Apple!!).
I have to take WG6d7's word for the inappropriateness of applikaatio even in mathematics. As an excuse I have that I've studied university level mathematics in Swedish, in which applicering is the correct term, but apparently not in Finnish. Mea culpa.
sovellus is the word used in newspaper articles, in adds, and even in most of the mobile devices themselves. My phone lists the apps I have under Sovellukset. The way words are used by professionals and how they are used by people in general differs quite a lot. For instance, the word teoria, "theory" would mean something very different to a physicist than it does to someone who is not a scientist. You can find odd pairs like this in every profession, whether you are talking about natural sciences, waiting tables, social sciences, farming, engineering, taking care of the elderly, forestry, fixing cars, cinema, carpentry, sports, cleaning the floors of a metro station on Sunday morning, or anything else. :)
Microsoft suffers from "not invented here" syndrome, meaning that they tout "a new, revolutionary blah-blah" with a fancy name only to be revealed that the method or technic has been around for a good while under another name by other companies. For instance they launched last year (?) "multi factor authentication" MFa (yes, that's the official MS way to write the abbreviation), but it is nothing more than two-factor authentication –since there are (currently) no more factors than two – which is the term everyone else uses.