Makerbot operators - if you have recently upgraded your firmware to Sailfish 7.4, you might have noticed that the extrusion line between the anchor and the start of your print has either disappeared, or have turned into a very thin wisp compared to before.
For some of us (myself included), that initial "pull cord" seemed to have helped with the initial sticking of the print to the print bed. If you find that you are not extruding plastic at the start of your print, you might find that turning on the Skirt plugin will help. The skirt outline will help prime the extruder, plus it's actually a good way to sanity check that your build will fit on the bed (it was a bigger issue back when I was printing on the ToM), and also check the tramming/level of your bed (the skirt should look evenly thick/wide all around -- if not, your bed is out of level).
See Dan Neman's comment about the change on the jetty-firmware group.