Social-bookmarking service Diigo has acquired web-clipping service Furl for an undisclosed amount. Furl’s parent company, Looksmart, received stock for the company, which it bought in 2004. With the deal, Diigo buys a company that offers services similar to its own—users can save and annotate portions of or entire web pages and share them with friends—allowing it to bolser its offerings without spending any cash. Furl never quite took off like its competitor Delicious (formerly known as del.icio.us); it attracts about 100,000 unique monthly visitors, according to Quantcast.

The acquisition comes amid consolidation in the social-bookmarking space. Just a couple weeks ago, Yahoo (NSDQ: YHOO) recently announced it was shuttering one of its bookmarking sites, Myweb, to focus on Delicious, which it acquired in 2005.

• After Downplaying It For Three Years, Yahoo Closes MyWeb Service
• Looksmart Acquires Furl.net