As can be expected, there has been a jump in the number of questions asked lately. Many were newbies asking various questions from the answerable-by-google kinds to the the inadvertently-expert type. And i have seen lots of "don't" advice posted in those threads.
Now, while i understand why it's bad to install apps from unsafe repos like extras-devel or go red-pill if you're not in the know, the danger of other things (like simply giving some commands in the terminal) is quite exaggerated. Many simply say "don't use the terminal if you're a noob". And i think they're pretty wrong.
I remember my first steps into linux. Gosh was i shaky. I had some experience with the awful windows command prompt, but everything was different under linux, so i wasn't very eager to use it. But i gradually got used to it. And most importantly, i understood that it's hard to do serious damage using just terminal commands. After the first time i killed my os (i think by changing something in the X configuration) and managed to reinstall everything the way it was quite easily, i was even more convinced.
Now think about them newbs. Maemo 5 is admittedly not perfectly user-friendly yet. Which means that you might not get full functionality if you don't get a little down-and-dirty. But the newbs are told not to do that, for fear of somehow doing some damage. What's even stranger is that sometimes they want to use something relatively harmless. And remember it's hard to do serious damage to linux without being root.
So my proposal is: let's give newbs some credit for being reasonably capable. Don't tell them off using terminal just because they don't have experience - they aren't going to get any either by not doing anything. Just warn when possibly damaging commands are involved (like rm - but don't go overboard, cat or grep can hardly be dangerous). And if something dangerous is involved, instead of recommending not to do it, warn about the danger and advise people to be ready to reflash if anything goes wrong - leaving them the choice of whether to do it or not
Sorry for the long text, hope you had the patience to read it

'nuff said.

Also, use the enter key more often.

He said hard - not impossible.
For someone to come up with issuing to root and run rm with parameters is most likely aware of what he is doing.

Also, use the backspace key more often.

Teach them to cd into a parent of the directory they want to delete first, so they can go:

without the leading slash. it could save their life

Users new to Linux should use terminal only on desktop system, and only if they want to learn about the OS itself. If they just want to use it, most mainstream distros are very user friendly, and there really is no need for noobs to use terminal.
On the other hand, noobs most definitely should not use terminal on their tablets!

I don't ever want to have to use the terminal. The whole point of a GUI is to get away from having to type everything. With a well written GUI, once it is installed, you should be able to do anything without going to whatever terminal is called in whatever OS you are using.

The terminal can be a dangerous place for us noobs.

I recently upgraded to ubuntu 9.10 and suffered the loss of sound problem.

I read some help guide and messed around in terminal, typed in some commands I knew absolutely nothing of, rebooted and BAM! laptop somehow didn't see my grub loader any more. Luckily I'm not that much of a noob and I knew how to safely get back from that, but where linux is concered I am pure noob, and linux scares me.

However, MrGrim, I do agree with you, the best way for me to learn is to use the terminal, and that is something I will continue to do, because I believe that if I did screw something up, the people here will help me fix it.

And you indeed may never, ever use the terminal, but as an ordinary user. For more advanced users terminal is still the place to be(even on Windows).
The thing is in the approach. Some of the things you will never be able to do in GUI, say shell scripting. It's just two different concepts.

what about using terminal to install deb files on n900. Is that safe or even necessary?

The problem is that even a simple mistake can cause a lot of pain.

Obviously sudo rm -rf / will be a problem...but if you know about sudo and rm's recursion/force options then you probably know the risks involved w/ using the Terminal. But how about:

rm /home/user/ some_harmless_directory_I_want_to_delete

No sudo, force option, yet big problem.

Or even:

cat whetever whetever2 > some_file_that_shouln't_be_overwritten

You can still mess up your system pretty good without sudo or even rm.