There is a website called dividendinvestor. It gives this info plus lots more relevant stuff on a companies dividends. For example, the 3 year dividend growth rate for WM is 6.99% and 5 year growth rate is 8.18%.
I like to look at the dividend per share and the consensus estimate for earnings. If we look at 2012 they paid $1.42 dividend / $2.10 consensus earnings estimate ( 3 quarters actual + 1 quarter estimate) which equals 67.6%. For 2013 I will guess they raise the dividend 6 cents for the year therefore $1.48 / $2.29 consensus 2013 estimate = 64.6%. However, looking at the cash flow statement for 9 months it looks like they stopped buying back stock.
According to the key statistics section on the Yahoo categories where you found the message board, the payout ratio is 76%. I'm not sure how current this data is, and it will change with quarter by quarter results. This stock appears to be having an increase in price going into earnings, and the REIT rumor caused a big jump up a couple days ago. This company can probably be a GDP dividend increase performer. It is not likely have growth much faster than that. If the management doesn't make bad mistakes, it is also unlikely to drop in value much.