Nothing. YAPM is a free and open source software, under GNU GPL 3.0 license. But if you want make a donation, you're welcome ! Just click on 'Donate' button in 'Help' view and you will be redirected to the donation page on sourceforge.net.
YAPM offers lots of useful features that Windows Task Manager does not have. For example, Windows Task Manager can't show loaded modules, threads, windows or handles. You can't search for a specific item, and you can't even select multiple items. If the standard Task Manager is a light and a useful tool, it is really limited.
Process Explorer from sysinternals offers some of these features, but remember Process Explorer is now owned by Microsoft, that's why you can't download its source code. So if you want to add some functions to Process Explorer, you can't. With YAPM, just ask in the forums and I'll try to implement it (or you can of course do it by yourself if you are able to do it). Moreover, YAPM offers A LOT OF features that Process Explorer does not have (windows, tasks, file, network management, advanced monitoring, jobs creation... etc).
And of course, neither Windows Task Manager nor Process Explorer is able to monitor remote systems :-)
Yes it's possible, as YAPM is still in development. Please report the bugs you found and/or your suggestion to YAPM's tracker. If you get the "crash report" window, PLEASE send the report to the tracker using "Send" button :-)
Yes, even if YAPM is using a driver, almost of functions are launched in user mode. That's why you are not able to execute some actions (e.g. kill some specific and protected processes, close some specific handles...etc.). In future releases, YAPM might will be able to process actions in kernel mode, but for now it's not the case.
Just launch YAPM with "-server" option. You can run "launch server.bat". The syntax is "YAPM.exe -server [-hide] -port PORT_NUMBER".
Have you search in the help ?
Have you try the forum ?
If not, you can contact me.