I found out what the button does the hard way - at a critical point during an important call I thought 'what does this button do?'......

haha it's funny same thing happened to me, but i was just talking with my dad and i called him right back... the more i use the included headset the more i like the "features"... including the asymmetric earpieces... it could have better sound quality for music perhaps, but i'm certainly going to hold off on buying a bluetooth thing (i had been looking at the motorola endeavor hx1)

search for 'DIY Lapel mic headphone adapter' (sorry, can't get the link to work) in the archive. i just did this mod, and it works great. it allows me to connect different headphones, external speakers or an mp3 recorder to the audio out without constantly stressing the tablet out jack. i like the nokia earbuds for their sturdy build, so i soldered a jack to them and still use them occasionally.