Attention managing partners: Do you like the idea of your associates using valuable bandwidth — both mental and electronic — to play Scrabulous or “poke” their friends on Facebook?

Allen & Overy did not. “We wanted to have our systems clear for client work and document storage,” says Kenneth Rivlin, a New York-based partner. A&O tried to ban Facebook use by employees in May 2007 but an associate insurrection convinced management to back down.

A&O wasn’t against all aspects of Facebook. “We saw both lawyers and staff using the site to build professional networks,” Rivlin says. Firm management saw the opportunity for lawyers to exchange resumes, make client contacts and circulate best practices memos about everything from writing a contract to structuring a deal.

So the firm tried a different tack — investing in Legal OnRamp, one of the first social networking sites specifically for lawyers. Legal OnRamp tries to deliver the professional services without the strippers and Filipino mail-order brides so popular on MySpace and Friendster.

The brainchild of Cisco Systems Inc. General Counsel Mark Chandler and former Perkins Coie lawyer Paul Lippe, Legal OnRamp has grown to more than 3,000 members from 200 firms and 400 companies after launching last year.

A site tour orchestrated by Lippe shows how users can browse individual lawyer bios, visit message boards, attend Q&A sessions and join groups. The site even offers Facebook-style updates on other lawyers.

A big problem with social networking sites — and a search of Facebook reveals that 42 Am Law 100 firms have networks — is that prospective members often use their work e-mail addresses, so the identity of the individual is tied to the firm, even when the individual is doing something online that the firm doesn’t endorse. Legal OnRamp has tried to solve that problem by requiring new users to be invited or approved before they join.

Some early adopters praise the site. “Social networking costs are minimal — it’s not like sponsoring a table at an awards dinner or printing brochures — so your return on investment is astronomic,” says Douglas Cornelius, a senior real estate associate with Goodwin Procter in Boston. Cornelius says he favors Legal OnRamp over other business networking sites like LinkedIn and LawLink because it’s interactive and offers access to potential clients through its in-house contacts. Cornelius’s one gripe with the site so far is that it has too many Silicon Valley types.

Lippe cites the 140-year-old Martindale-Hubbell directories as proof that lawyers have always felt a need to be connected. And by limiting the network to lawyers, Lippe hopes that the site will stay focused on law, not emo bands.