Seriously, I appreciate those who attempt to keep rosters up-to-date. They have a thankless job that gets tedious. I attempted to just keep one team - the Cincinnati Reds - updated. Every now and then, you find players still on rosters who have been cut, and adding waiver wire pick-ups and such.
You scour transactions pages from about four or five different websites because if you rely upon just one site, you might get unreliable information. So you have to compare information and if you can confirm a transaction a couple ways, then you can pretty much take it as accurate. Finding several sources of accurate minor league transactions is difficult.
I certainly appreciate the effort made by those who do keep up with such information!