San Francisco-based SynthaSite, which operates an online site which helps users build their own web pages, said Thursday that it has agreed to acquire Clickpass, a developer of authentication software. Financial terms of the buy was not disclosed. Clickpass provides secure authentication services via OpenID and related tools. Clickpass founder and CEO Peter Nixey joins SynthaSite as VP of Trust, Identity and Reputation. SynthaSite is venture backed by Columbus Venture Capital. Clickpass allows users to reduce the number of password and usernames required for logging into various Internet sites, including Wordpress blogs, Disqus, Scribd, and Ma.gnolia.