Sugar, the blog network which runs celebrity site PopSugar and fashion site FabSugar, among others, just launched a new blogging tool called OnSugar. Sugar says OnSugar is "sweet and simple publishing." A bit too simple, it turns out. OnSugar looks like a blatant ripoff of Tumblr, the kindergarten-simple blog site popular with Brooklyn and San Francisco's most self-involved Internet users. OnSugar seems to have copied Tumblr's look, feel and features, adding some girly pink. But Sugar's copying was more than just superficial.Many popular blog services offer "bookmarklets" — software tools, installed in browsers, which allow users to quickly post an article they're reading online. The "Share OnSugar" bookmarklet's source code appears identical to the code Tumblr founder David Karp and engineer Marco Arment wrote for the "Share on Tumblr" bookmarklet. Compare the two, above: Sugar hasn't bothered to do much more to the user interface besided adding tags and categories, which are hidden "advanced options" in Tumblr's bookmarklet. The code is an even closer copy. Here's the problem for Karp: Though popular with a certain crowd, Tumblr is far from mainstream. So users who fall in love with OnSugar blogs may never learn about the original. We'd point out that Tumblr itself is just a happily dumbed-down ripoff of LiveJournal, which predates it by nearly a decade and offers all the privacy features Tumblr users have been begging Karp for, but after OnSugar's more blatant blow, that seems cruel.