The site is getting ready for this year's fundraising round
It's that time of the year again. Yes, the time when you get to see Jimmy Wales' mug plastered all over Wikipedia for a couple of months. It's not all that you're going to see, this year Wikipedia has an especially subtle blue banner waiting for you as well.While the 2012 fundraising campaign is not fully underway, Wikipedia may still be testing banners, messages and so on, it's very close to getting underway.
After all, it's been testing all sorts of variations on banner layout, colors and text for the past few months.
It seems to have settled on a blue background banner, which you'll be hard pressed to ignore, with text describing how Wikipedia is one of the biggest sites on the planet yet runs on ads and has no other revenue source than donations.
The text likely varies from place to place and Wikipedia may still be doing A/B testing on it, so you'll be seeing different versions depending on where you are and other factors.
It goes without saying, if you find Wikipedia useful, that is to say, if you use the internet, you could help out Wikipedia with a donation.