Sorry, when a headline says "home sales fell 41% in February" I do not assume year over year, I assume month over month. This post's headline is needlessly provocative and misleading. Take it to reddit.
Month on month tells us nothing (in this extreme example). Year-on-year (ie, Oct 09 v Oct 08) give us an indication of strength or otherwise in a market, without seasonable variations.
Having worked with 120+ Real estate agencies (in Australia - US cycle will differ) I can tell you that every year Jan will be 'down' from Dec, Feb will be up, September will always show an increase over August, and Dec will usually be bigger than Nov.
Reporting just those figures would look like the 'housing market' was an unpredictable roller coaster - up one month, down the next, when will it end, think of the children!?
Sure, in many instances (your business cashflow, for instance) both data points are useful. But year-on-year removes more variables and is therefore more important.
Ellyagg also said "This post's headline is needlessly provocative and misleading." , which prompted me to respond.
To reiterate (and not to clarify, because my original comment is clear): When the press reports rises and declines, if they do not explicitly say year over year, they are talking month over month. Indeed, this VERY article contains an example of it, with the press reporting that home sales were up 4.7%. The original title of this submission, before it was edited to include "year over year", specifically played upon this implied and incorrect comparison to provoke a response.
Indeed, I'm not the only one who found the headline misleading; my comment had been voted up to at least 5 shortly after I posted, and before the headline was altered and your tangential comment sent people on a wild goose chase.
As JacobAldridge points out, it is used to account for seasonal variation; an article that looks to month over month figures would seem anomalous for this same reason. But it takes knowing some of the nuance of the industry and how it is reported to understand the what and why of the convention. I'm not a realtor, nor do I work with realtors; I just find that sector interesting to read about, enough so that some of the nuance rubs off. :-)
I actually can't think of any sales figures that are relevant month to month.
Basically any way you slice it you can argue the other person is full of shit. That doesn't mean anyone actually is.