The consulate will tell you it's not wise but I have been living here doing that a number of times. (I'll get my papers cleared about the time I am done here) It's a good excuse to travel and see the rest of Europe!
If you mean you have been breaking up your 90 days then yeah that will work.
If you mean crossing out of the Schengen every 90 days and getting more time that is a thing of the past. As of January 1st. It is 90 out of 180 days as has been said above.
It really is nonsense that this is the rule for the WHOLE Schengen as there are loads of countries in the zone and it makes it impossible for someone to take a long wandering trip anymore.