I'm a pretty bouncy person myself and tend to over-use exclamation marks. But I don't like it when websites I want to use try to make their copy bouncy and perky; it just seems artificial and irritating. LJ's copy is really bad that way; it seems patronizing, not cheerful. And yes, we are pretty excited about Dreamwidth, but I don't think the site should be trying to emotionally manipulate people into artificial excitement.