Using data from almost 9 years of pageviews at this blog, I fit a trend line with an OLS regression model where the dependent variable is the 30 day moving average (the blue line) of page views as measured by Typepad (where x is the time period). Here are two contrasting 1000 day forecasts (the trend line beyond the blue). First, the R2 maximizing cubic function (the linear model has an R2 of near zero):
Second, here is the quadratic:
Which forecast would you choose? I'm hoping for the quadratic because the light is at the end of the tunnel.