I started using BOINC around 2010.
I used it on Windows, and on Linux so far.
The last time was years ago.
Somewhat surprising to read that Seti@Home is now defuct.
The last time I used BOINC it was still worked.
As I currently know, it was the most popular BOINC project.
Or at least one of the most popular BOINC projects.
Either way, currently I do not have a PC, nor a laptop, so currently I cannot use it.
You can also run BOINC on Android based devices (tablets, phones, etc.). It runs while your device is charging.
Maybe once or twice I used it on Android too.
Not much.
Android is also Linux.
But I know that not every project support Android.
And some projects support only certain hardwares. For example AMD or Nvidia video cards.
Currently I do not have a separate Boinc account, but I have accounts with various Boinc projects.
For example the Milkyway@Home project.
I used it with Windows and with Mac PCs and laptops so far.
There's not really a separate BOINC account but I think all the accounts for the individual projects are linked for statistics purposes if you use the same e-mail address.