Can someone please tell me what it does in a song? As in like what does it provide?
Please be gentle because I am new to guitars, and I am not being a hypocrite, I genuinley want to know what it does to contribute to a song.
well, this will sound retarded, but it covers the bass notes, most indie bands udsw it in its wriost context, to play a really boring bass line on the root note of hwatever vhord the guitarist is doing, better band often use it to either fill ingaps in the music, oasis do this, some let the whole song revolve around the bass line which drives the song (see longview by greenday and pink floyds money) and only occasionaly do they ride other everything else (see the who, my genration). once you here these ull see bass work in different context and doing different things, and it should help, but a good soilid, variaing bass line wil drive the song allowing more freedom for other things, so bass is important becuase it adds depth to the music
Often you don't notice the bass until its gone. Without it the song is empty.... Also, it keeps the drummer in time. The bassist KEEPS THE TIME.
I like to think of it as the "glue" between the drummer and guitar(s), as most songs without a bass-line sound incomplete. Some songs can pull it off though.

I think a great example is to listen to "Inside Looking Out" by Grand Funk Railroad, as it has a great bass line and how the bass and guitar play off of each other, sounding really smooth. Mel Schacher FTW!!!