is s0.2mdn.net malware?

I've got freezes requiring restart more than once a day (iMac mid 2010, 3.06 ghz processor, beefed up yo 12 Gb memory, using El Capitan 10.11.3). Intermittently I get asked whether "s0.2mdn.net" can use my current location. I've seen references online to this being something to do with Google adware, and also instructions to remove it by unpicking a Safari extension in preferences, but I can't find any such extension. Could this be what's causing my freezes?