comScore, the firm which tracks Internet traffic trends, issues web rankings every month on the top web sites. Today, two Southern California firms showed up on the firm’s top 10 list of companies having increases in unique visitors: JibJab and Buzznet. JibJab, the Santa Monica-based firm which runs an online content site focused on comedy and humor content, showed up as number two in the biggest increase in uniques for December; the firm went from 1.7M uniques to 4.4M uniques, a 156% increase in the number of visitors. Buzznet, which is based in Los Angeles and operates a social media, music-focused social networking site, also saw a big bump, going from 3.1M users to 4.97M unique users in December, up 60%. JibJab is venture backed by Polaris; Buzznet is backed by Anthem Ventures and Redpoint.