Question 1002195
It's a little easier if you set x, the year, to 1,2,3,...,8
I get y=146.93x+352.43.  
goodness of fit is r^2, and you get that on your calculator by pressing 2nd 0 and then press x(-1) to get you to the D section of the catalog.  Diagnostics ON, and hit enter once to get it in and a second time to run the regression again.
r^2 is the goodness of fit, which is very high  or 0.996.  This suggests that the line is very good in predicting y from x.
The slope is the increase in number of Internet users in millions every year.
The intercept is the number of Internet users at year 0, which in this instance (for me) is 352 million in 1999.  That may actually make sense, but often, the intercept is nonsense and you can ignore it.  The slope and the r^2 are what you want.