tedster - 4:27 pm on Mar 2, 2012 (gmt 0)

should I stop all link building work with keyword targeted anchor text

At a guess, I'd say "yes - stop all that effort to control backlinks directly." It can be different in different market verticals, but as a general rule, Google is devaluing or even penalizing links that are under the webmaster's direct control. Too much matching anchor text is a dea giveaway that the backlinks are not natural - not "freely given, in-content editorial links" from a different site.