Picasa Web Albums, the online extension of Picasa, has recently added tags and search. Now you can see a tag cloud in the right sidebar of a public gallery (instead of increasing the font size for frequent tags like in Flickr, Google chose to show the number of photos that have a certain tag). This way, it's easier to explore someone's photos without going to each album.

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The number of photos you can upload to an album has been increased from 300 to 500. </img> </img> </img>