With the resignation of Larry, there is a much less pressing need for funds. Therefore, all plans to put advertising of any kind on the wikipedia is called off for now.
We will move forward with plans for a nonprofit foundation to own wikipedia, and possibly to solicit donations and grants to help us carry out our mission. (Ironically, I think that grant money would come with many annoying strings attached, which we could not accept, comparted to advertising money, which is virtually 100% string-free.)
Just as the National Geographic Society is supported in large part by advertisments in the National Geographic Magazine, I expect this to be a potentially necessary thing at some point in the future, if we wish to have an impact beyond our own little corner of the Internet. (And, I think we all do.)
But for now, there's no pressing need unless and until we find chaos descending on us from the lack of constant oversight.
The hosting of Wikipedia I can continue to do for no charge for the foreseeable future. Even if Wikipedia traffic were to grow by a factor of 10, I would be willing to absorb all the bandwidth and hardware costs. If it grows beyond a factor of 100 or 1000, obviously, alternative solutions would have to be found.