I just thought it would be interesting to share this bit with readers. Below is a graphic of how many users *added* a certain mashup to their Sampa site on month of December. Notice that it doesn't represent how many users are using a specific type of mashup because users might have added it and remove it later or users might have added before the month of December.
YouTube (42%) is the #1, followed by Flickr (38%) very closely. Then we have Blogger (9%), Delicious (6%) and BlueDot (5%).
You know when something is big when most distributions lists that you belong to discuss the same topic, bloggers discuss the same topic, mainstream media (even your local channel) talk about it and when you get home your wife is talking to you about the same thing.