Yahoo Meme is kind of like a Twitter / Facebook mashup. When you create an account, you are presented with an empty blog which you can template with your choice of avatar and background and populate with text posts, music, videos and pictures. You can also comment underneath any of your content. You can follow people and repost their content, similar to retweeting on Twitter. View a sample Meme profile to get a feel for it.
Meme’s mascot is a cartoon dog. Not quite as cute as the Twitter bird but close enough.
With Yahoo launching Meme to the Spanish speaking market, it seems they are getting closer to building a potential rival to Twitter.