One of the things that make the web exciting for museums is that setting up virtual exhibitions is so easy. You don't need much money, nor altering the physical structures of your museum in any way. This fact is going to change the way museums and private companies collaborate: you don't need "heavy" sponsorships to make your ideas come true. Moreover, new kinds of sponsorships are coming to life. Private firms can give you money, but not money only: they can give you visibility on their websites; they can give you graphic artists or programmers you could never afford; they can host your pages on powerful servers with fast connections. Now that the Internet is boosting all over Europe and private companies have started investing more money on their web operations, web sponsorships are growing in importance, and getting companies' attention is becoming easier for a museum. Web sponsorships can also be important as a first step in establishing collaboration; positive results can drive to sponsorships to the real museums. On the other hand, you have to take web operations very seriously, in order to make your sponsors happy. The Milan Science Museum web staff has been setting up this kind of sponsorships since the very first days of the website; some of them have proved successful, while others have produced little or no results. By presenting some of this case-histories, we hope to provide other museums ideas for their own web-based sponsored operations.