I realize it's easy to assume that IDC is intentionally boosting Android/MS for nefarious or financial reasons, but it isn't necessarily the case. Back during my misspent youth as a physics grad student I took a course in cosmology, and I still remember how, on the very first day, the professor made several heroic assumptions about the universe. I remember a guy asking why we made these assumptions, and the professor replied that we had to, if we didn't we really couldn't get anywhere at all. The entire field of cosmology is built on these approximations and if the universe is radically different than that then we're just stuffed.
Often analysts end up making similarly huge assumptions, such as that product shipped is a good indication of product sold, or that Nokia will carry their market share over to WP7, and I suspect it's for the same reason. If they didn't make them then they wouldn't be able to do anything at all.
The really bad thing is when they make these huge assumptions and don't note it anywhere in the analysis.
there is no question IDC provides paid services to MS, that's a fact. eg, see this EULA, search for "IDC". they provide financial info for a lot of MS services. i have to assume they get paid for that.
their conflict of interest is blatant. but web "journalism" ethics are so pathetic anyway that no on calls them out for it.