I seem to go over 6 months on about 30%. Places currently not responding to queries include Crescent Review (going on a year), Nidus (for poetry), New Delta Review. I'm waiting on a few others, too, but at least they've let me know they were still considering. Some turned out never to have received the work, or turned out to have already sent notification that I never received (and once there was an acceptance letter that I never got... luckily they sent a follow up). So that's why I query. No sense waiting and wondering for too long only to find out they never saw the piece.
Re Meridian, I sent them my story in March 2004. My last query was in March 2005, and I cc'd several eds and the faculty advisor... not a word. I think I've revised that story several times since then, it having been 14 mos. So if they wanted to publish it, I doubt I even have an electronic copy of the version I sent. But anyway it bugs me. I always want closure.
It seems there are more problems with never hearing back from venues now that there's so much email correspondence and email submissions. I messed up with StoryQuarterly...logged onto their site and created and account the day before they opened the transom. Made a notation in my spreadsheet. Then forgot to go back the next day and upload the story. So thought I was waiting all this time, when I'd never actually sent it in. And Gargoyle sent an email rejection that probably got eaten by my spam filter. So maybe that's what happened with Meridian, too.
I sent a story a LOOOONNNNG time ago to New Stone Circle; am guessing they're defunct, but how hard would it be to drop my self-addressed stamped postcard in the mail telling me so? (The address looked like the editor's home; it's what you get when do a white pages search on her, too.)