I am disappointed with Google maps- I thought it would be intuitive and simple, but it actually isn't. I created a map of Berkeley, and was going to add locators for the various library branches, but I am still struggling to figure out how to control the appearance and scope of the map- it keeps switching to the Google earth view, and sometimes goes off altogether and I wind up in Wichita! Clearly need to spend more time with this. The add-on tools are really cool- I like the real estate finder (I saw it first in use on a realtor's site) and the earthquake locators. It looks like it's easy to add the map to your blog or website once it looks the way you want it to.
Upon further explorations, I managed to create a map with a placemark marking the location of the main branch of the BPL, and then added a photo of the building into the placemark- a process that was not very lucidly explained in Google help. There is no actual "add content" button on the Create New Map tab- you have to go to Browse the Directory, or you have to add a placemark and add your content to that.
It is fun, though, and I think you can do alot with this kind of a tool. It will be interesting to see how easy it is to mashup.My first map effort.