Ugh. 'Infinite' vacation policies are starting to infect corporaculture. I work for a megacorp (that I actually rather enjoy working for) that recently went this way, and since my megacorp is a bit of a trend setter, you can expect it to spread. During the explanation meeting, it was made clear that we really aren't supposed to take more vacation than what we used to have, but that we are expected to still actually take about as much vacation as we used to have ... so essentially a no-change there. As far as I can tell, it's mostly about
1) Making it so that employees can't take vacation at times that are particularly bad for a project because they're 'entitled' to it. This was already frowned upon (we always did get to use our vacation eventually, so it wasn't so bad), but now it's in writing -- which is good, rules should be written.
and, more importantly to the megacorp:
2) Eliminating owed vacation from their books & marginally reducing cost. Now if somebody quits or is canned, they're not owed a payout. I'm guessing the average employee will probably also take a couple of days less than they did under the old system, yielding a further savings.